星形成ゼミ
2019/08/09
SFN 319 #12-#21

長谷川哲夫（国立天文台）

1

Nicolás Cuelloand Cristian A. Giuppone

1

Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Santiago, Chile, e-mail: ncuello@astro.puc.cl
Núcleo Milenio de Formación Planetaria (NPF), Chile,
3
Universidad Nacional de Córdoba, Observatorio Astronómico - IATE, Laprida 854, X5000BGR Córdoba, Argentina
2319 Planet forma8on and stability in polar circumbinary discs
Cuello1,2
Cris8an
A. Giuppone3
Received
30 Julyand
2018/ Accepted
25 June 2019#12 Nicolás
arXiv:1906.10579v1 [astro-ph.EP] 25 Jun 2019arXiv:1906.10579v1 [astro-ph.EP] 25 Jun 2019

ABSTRACT
Context. Dynamical studies suggest that most of the circumbinary discs (CBDs) should be coplanar, i.e. the rotation vectors of thebinary and the disc are aligned. However, some theoretical works show that under certain conditions a CBD can become polar, whichmeans that its rotation vector is orthogonal with respect to the binary orbital plane. Interestingly, very recent observations showed thatpolar CBDs exist in Nature (e.g. HD 98800).
Aims. We test the predictions of CBD alignment around eccentric binaries based on linear theory. In particular, we compare prograde
and retrograde CBD configurations. Then, assuming planets form in these systems, we thoroughly characterise the orbital behaviourand stability of misaligned (P-type) particles. This is done for massless and massive particles.
Methods. The evolution of the CBD alignment for various configurations is modelled through three-dimensional hydrodynamical
simulations. For the orbital characterisation and the analysis stability, we relied on long-term N-body integrations and structure andchaos indicators, such as e and megno.
Results. We confirm previous analytical predictions on CBD alignment, but find an unexpected symmetry breaking between prograde
and retrograde configurations. More specifically, we observe polar alignment for a retrograde misaligned CBD that was expected to
become coplanar with respect to the binary disc plane. Therefore, the likelihood of becoming polar for a highly misaligned CBD ishigher than previously thought. Regarding the stability of circumbinary P-type planets (aka Tatooines), polar orbits are stable overa wide range of binary parameters. In particular, for binary eccentricities below 0.4, the orbits are stable for any value of the binary
mass ratio. In the absence of gas, planets with masses below 10 5 M have negligible e↵ects on the binary orbit. Finally, we predictthat Polar Tatooines should be searched around mildly eccentric equal-mass binaries.
Key words. planets and satellites: dynamical evolution and stability – protoplanetary discs – binaries: general – methods: numerical– hydrodynamics

1. Introduction
Planets appear as common by-products of the star formation process within molecular clouds (Chiang & Youdin 2010). At early
evolutionary stages (class 0/I), the fraction of stellar binaries
and higher-order multiple systems is remarkably high: between
30% and 70% (Connelley et al. 2008; Chen et al. 2013). Consequently, protoplanetary discs can be severely a↵ected by binary formation and stellar flybys (e.g Bate 2018; Pfalzner 2013).
Given the stochasticity of these processes, highly asymmetricaldiscs naturally form in time-scales of the order of a few hundredsof kyr. Therefore, planet formation is also expected to occur ina broad variety of misaligned discs (Bate 2018; Cuello et al.
2019a). Currently, about a hundred planets have been detected
in multiple-star systems (Martin 2018). There is however a striking tension with the more than 3 700 planets detected1 aroundsingle stars (Batalha et al. 2013).

most binaries do not eclipse renders P-type planet detection extremely challenging. On the other hand, recent stellar-tidal evolution models of short-period binaries show that the binary orbital period increases with time (Fleming et al. 2018). This translates into a larger region of dynamical instability around the binary, which could explain the lower frequency of P-type planets
compared to S-type planets. Based on the available data, typical planets found around binary stellar systems have a radius of
the order of 10 Earth radii and orbital periods of about 160 days
(Martin 2018). For instance, around a binary system with total
mass equal to 1 M , this corresponds to an orbit with semi-major
axis of approximately 0.35 au.

2
Previous theoretical studies suggested that the disc-binary interaction, namely the gravitational torque, should align the discwith the binary orbital plane in time-scales shorter than the disc

1 Department of Astronomy, University of California at Berkeley, Campbell Hall, CA 94720-3411, USA

arXiv:1906.03269v2 [astro-ph.EP] 17 Jun 2019

2 Department of Earth and Planetary Science, University of California at Berkeley, McCone Hall, Berkeley, CA 94720-4767, USA
3 Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA

Department of Physics and Astronomy, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA
319 The5 4Degreeof Alignment Between Circumbinary Disks and Their Binary Hosts
Department of Physics and Astronomy, Vanderbilt University, 6301 Stevenson Center, Nashville, TN 37235, USA
Czekala,1 , ∗ Eugene Chiang,1,
2 Sean M. Andrews,3 Eric L. N. Jensen,4 Guillermo Torres,3 David J. Wilner,3 Keivan G. Stassun,
6 Department of Physics, Fisk University, Nashville, TN 37208, USA#13 Ian5, 6 and Bruce Macintosh7
7

Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, CA 94305, USA
arXiv:1906.03269v2[astro-ph.EP] 17 Jun 2019

ABSTRACTAll four circumbinary (CB) protoplanetary disks orbiting short-period (P < 20 day) double-lined
spectroscopic binaries (SB2s)—a group that includes UZ Tau E, for which we present new ALMA
data—exhibit sky-plane inclinations idisk which match, to within a few degrees, the sky-plane inclinations i? of their stellar hosts. Although for these systems the true mutual inclinations ✓ between
disk and binary cannot be directly measured because relative nodal angles are unknown, the nearcoincidence of idisk and i? suggests that ✓ is small for these most compact of systems. We confirm thishypothesis using a hierarchical Bayesian analysis, showing that 68% of CB disks around short-periodSB2s have ✓ < 3.0 . Near co-planarity of CB disks implies near co-planarity of CB planets discoveredby Kepler, which in turn implies that the occurrence rate of close-in CB planets is similar to that aroundsingle stars. By contrast, at longer periods ranging from 30–105 days (where the nodal degeneracy canbe broken via, e.g., binary astrometry), CB disks exhibit a wide range of mutual inclinations, fromco-planar to polar. Many of these long-period binaries are eccentric, as their component stars are too
far separated to be tidally circularized. We discuss how theories of binary formation and disk-binary
gravitational interactions can accommodate all these observations.
Keywords: protoplanetary disks — stars: pre-main sequence — (stars:) binaries (including multiple):close — (stars:) binaries: spectroscopic — planet–disk interactions — methods: statistical— stars: individual (UZ Tau)
1. INTRODUCTION

A fact no less true for being so commonly stated, mostsolar type stars do indeed reside in binary or higher
multiplicity systems (Raghavan et al. 2010). The influence of binarity on star and planet formation has primarily been addressed from the perspective of circumstellar disks or planets perturbed by an external stellar
companion (i.e., in the “S”-type configuration; Dvorak
1982). For example, the presence of a binary companion
with semi-major axis a < 50 au will truncate the outerris et al. 2012), possibly reducing the planet occurrence
rate (Wang et al. 2014; Kraus et al. 2016). By comparison, at the closest binary separations (a . 10 au),massive disks will most likely be circumbinary (i.e., in
the “P”-type configuration; Dvorak 1982; Harris et al.
2012).
E↵orts to study planet formation in the circumbinary
3
sense were given new urgency by the Kepler mission’s
discovery of circumbinary (CB) planets orbiting eclipsing binary (EB) stars (e.g., Doyle et al. 2011; Welsh

319 2019
Dynamics
of magne8c
ﬂux tubes
in accre8on discs of T Tauri stars
2019 June 12. Received
June 11; in originalform 2018 December
7E. Dudorov,1‹ S. A. Khaibrakhmanov 1,2‹ and A. M. Sobolev2‹#14 A.
MNRAS 487, 5388–5404 (2019)
ABSTRACT

Dynamics of slender magnetic flux tubes (MFTs) in the accretion discs of T Tauri stars isinvestigated. We perform simulations taking into account buoyant, aerodynamic, and turbulent
drag forces, radiative heat exchange between MFT and ambient gas, and magnetic field of thedisc. The equations of MFT dynamics are solved using Runge–Kutta method of the fourthorder. The simulations show that there are two regimes of MFT motion in absence of external
magnetic field. In the region r < 0.2 au, the MFTs of radii 0.05 ≤ a0 ≤ 0.16 H (H is the scaleheight of the disc) with initial plasma beta of 1 experience thermal oscillations above the disc.
The oscillations decay over some time, and MFTs continue upward motion afterwards. Thinneror thicker MFTs do not oscillate. MFT velocity increases with initial radius and magnetic fieldstrength. MFTs rise periodically with velocities up to 5–15 km s−1 and periods of 0.5–10 yr
determined by the toroidal magnetic field generation time. Approximately 20 per cent ofdisc mass and magnetic flux can escape to disc atmosphere via the magnetic buoyancy overcharacteristic time of disc evolution. MFTs dispersal forms expanding magnetized coronaof the disc. External magnetic field causes MFT oscillations near the disc surface. Thesemagnetic oscillations have periods from several days to 1–3 months at r < 0.6 au. The
magnetic oscillations decay over few periods. We simulate MFT dynamics in accretion discs
in the Chameleon I cluster. The simulations demonstrate that MFT oscillations can produce
observed IR-variability of T Tauri stars.
Key words: accretion, accretion discs – diffusion – MHD – ISM: magnetic fields – ISM: jets
and outflows – stars: variables: T Tauri, Herbig Ae/Be.

RO D U C T I O N

r of observations show that young stellar objects (YSO)

According to modern theory of star formation, young stars withthe accretion discs form as a result of gravitational collapse ofrotating molecular cloud cores with magnetic field (see reviews by

4

nloaded from https://academic.oup.com/mnras/article-abstract/487/4/5388/5518368 by National Astronomical Ob

eral University, 51 Lenin str, Ekaterinburg 620000, Russia

Double-peaked [O I] Proﬁle: A Likely Signature of the Gaseous Ring around KH 15D
Min Fang1,21, Ilaria Pascucci2,3, Jinyoung Serena Kim1,2, and Suzan Edwards4

Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
2
Earths in Other Solar Systems Team, NASA Nexus for Exoplanet System Science, USA
3
Department of Planetary Sciences, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721, USA
4
Five College
Astronomy
Department,College,Edwards4
Northampton, MA 01063, USA
Min Fang1,2 , Ilaria Pascucci2,3, Jinyoung
SerenaKim1,2 ,Smithand Suzan
Received
2019
March
11;
revised
2019
June
6;
accepted
2019
June 11; published 2019 July 1
The Astrophysical Journal Leiers, 879:L10 (6pp), 2019 July 1

319 Double-peaked [O I] Proﬁle: A Likely Signature of the Gaseous Ring around KH 15D#15
Abstract
KH15D is a well-known spectroscopic binary because of its unique and dramatic photometric variability. The
variability is explained by a circumbinary dust ring, but the ring itself was never directly detected. We present a
new interpretation of the double-peaked [O I] λ6300 proﬁles as originating from the hot disk surface of KH15D.
By modeling these proﬁles, we measure emitting radii between ∼0.5 and 5 au, basically a gaseous ring very similar
in radial extent to the dust ring inferred from modeling the system’s photometric variability. We also discuss thepossibility that external photoevaporation driven by ultraviolet photons from the nearby massive star HD47887
has truncated the outer edge of the disk to the observed value.
Key words: open clusters and associations: individual (NGC 2264) – protoplanetary disks – stars: individual (KH
15D) – stars: pre-main sequence
1. Introduction
KH15D is a pre-main sequence (PMS) spectroscopic binary(A+B) with near-equal-mass components (0.715 Me for Star A
and 0.74 Me for Star B), high eccentricity (e ≈ 0.6), asemimajor axis of ∼0.25au, and a period of 48.37 days
(Johnson et al. 2004; Winn et al. 2006; Aronow et al. 2018). It
is a member of the NGC2264 cluster at ∼750 pc, based on themembers from Venuti et al. 2018 and Gaia Data Release 2
parallaxes, and the cluster is about ∼2–6 Myr old (Naylor 2009;Lim et al. 2016). KH15D exhibits unique and dramatic longand short-term photometric variability (e.g., Capelo et al.
2012). From 2006 to 2009 Star B was fully occulted, while
after 2010 Star A became occulted; currently, the entirety ofStar B is visible at each apastron passage (Aronow et al. 2018)
The short-term variability has the same period as the binary(Kearns & Herbst 1998; Hamilton et al. 2001; Herbst et al.
2002; Johnson et al. 2004). However, the large depth (several
magnitudes) and long duration (days to tens of days) of theeclipse, in combination with the time variability, cannot besolely attributed to the binary. Additional occultation by
circumbinary matter must be invoked (Hamilton et al. 2001;
Herbst et al. 2002).
A nearly edge-on, warped, and precessing circumbinary ring

(Tokunaga et al. 2004; Aronow et al. 2018). Finally, the systempresents broad Hα line proﬁles, indicative of active accretion(Hamilton et al. 2012), perhaps funneled from gas surrounding
both stars (see the case of the spectroscopic binary DQ Tau;
Muzerolle et al. 2019). The presence of a jet and ongoingaccretion point to the presence of a gaseous disk.
Here, we interpret the double-peaked [O I] λ6300 proﬁlesfrom KH15D as originating from the surface of this gaseous
disk (Section 2). Modeling of the line proﬁles reveals that theemitting gas is radially conﬁned (Section 3). We discuss how
external photoevaporation could have truncated the gaseous
disk to the outer edge inferred from our [O I] λ6300 modeling(Section 4).
2. Double-peaked [O I] λ6300 Proﬁles
The spectroscopic data presented in this work were obtained
from the Very Large Telescope (VLT)/Ultraviolet and Visual
Echelle Spectrograph (UVES), European Southern Observatory(ESO) archive for three nights in 2001 and six nights in 2004
5with a spectral resolution of ∼42,000 and have been alreadypublished in Hamilton et al. (2003, 2012) and Mundt et al.
(2010). We extracted the raw data from the ESO archive5 andreduced them with the ESO UVES pipelines under the ESO

Laura Flagg1
1, Christopher M. Johns-Krull1,2, Larissa Noﬁ3,4, Joe Llama3
Gregory Mace5, L. Prato2,3, Kendall Sullivan5, D. T. Jaffe5, andDepartment of Physics and Astronomy, Rice University, 6100 Main Street, MS-108, Houston, TX 77005, USA; laura.ﬂagg@rice.edu
2Visiting Astronomer at McDonald Observatory of The University of Texas at Austin, USA
3
K
Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001, USA
4
Laura Flagg1 , Christopher
Johns-Krull1,2,
Larissa
Noﬁ3,4,
Joe2680
Llama3, L. Prato2,3,
KendallHISullivan5, D. T. Jaﬀe5 , andInstitute forM.
Astronomy,
Universityof Hawai’i
Manoa,
Woodlawn
Drive, Honolulu,
96822, USA
5
McDonald Observatory and the Department of Astronomy, The University of Texas at Austin, Austin, TX 78712, USA
Gregory Mace5
Received 2019 February 18; revised 2019 May 31; accepted 2019 June 6; published 2019 June 21

319 CO Detected in CI Tau b: Hot Start Implied by Planet Mass and M#16
The Astrophysical Journal Leiers, 878:L37 (5pp), 2019 June 20

Abstract
We acquired high-resolution infrared spectra of CI Tau, the host star of one of the few young planet candidates
amenable to direct spectroscopic detection. We conﬁrm the planet’s existence with a direct detection of CO in theplanet’s atmosphere. We also calculate a mass of 11.6 MJ based on the amplitude of its radial velocity variations.
We estimate its ﬂux contrast with its host star to get an absolute magnitude estimate for the planet of 8.17 in the Kband. This magnitude implies the planet formed via a “hot start” formation mechanism. This makes CI Tau b the
youngest conﬁrmed exoplanet as well as the ﬁrst exoplanet around a T Tauri star with a directly determined,
model-independent dynamical mass.
Key words: planetary systems – planets and satellites: formation – stars: individual (CI Tau)

The Astrophysical Journal Letters, 878:L37 (5pp), 2019 June 20
Table 1

1. Introduction
Parameters of the CI Tau System

Flagg et al

Of particular interest from this detection is the contrast ratio

hot-Jupiter atmospheres and their main-sequence host stars’
betweenstar2010;
and Brogi
the planet.
By inserting
continuum (e.g.,
Snellenthe
et al.
et al. 2012;
Birkby simulated planets
惑星形成のメカニズムと
Observations of young exoplanets are key to understandingatrandomsystemic
andorbitalvelocities,
we can estimate theet al. 2013; Rodler
et al. 2013). Near-infrared spectra are used
Parameter
Value
形成初期の原始惑星の温度
planet formation. Models for giant planets indicate that planets
contrast
ratio inneededto produce
the signal
O we see. Our bes
to detect molecules
commonplanetary
atmospheres
like H2that(M)
0.90±0.02
can formMwith
very
different
temperatures
at
early
ages.
It
is
:
•
Grav.
Instability→hot*
estimate
forfromthe different
ﬂux ratiophases
betweenstar+disk and planet isand CO. By using
spectrain thetheplanet’soften assumedthat
K* (km s−1) gravitational instability produces hot 0.950±0.207
94
•
Core
accre8on→cooler
orbit, the mediansignal ourcan estimatedbe simply subtracted
356stellar
veiling ofout,
1.08±0.16 for the
69 . Withplanets, while
core
Distance(pc)accretion forms comparatively cooler and 158.0±1.2
while the planet’s
signal, which
is movingat Tauhundreds
of is consistent withleast-veiled
observationofCI(whichless luminous planets (Marley et al. 2007b), although it may be
kilometerspersecond,remains,
allowing
foradirectdetection
otherperiod(days) models to produce planets at a8.9891±0.0202
観測 veiling measurements for CI Tau—Sokal et al
possible Orbitalfor bothformationof the planet’s submitted),
spectrum.
Eccentricity
0.25±0.16
this results
in a star-to-planet ﬂux ratio of
range of temperatures (Helled et al. 2014). To better distinguish• Myr
40 observa8ons
2014-2018
CI Tau is a ∼2–3
old, K7,
classical
T Tauriratio
star. Johns54
Angleofperiastron(°)
31±56
172
.
Based
on
the
contrast
the planet andbetween these possibilities, young planets with model-inde37• detected
Immersion
Gra8ngInfrared MJ betweeni=8.08±1.53
planetKrull et al. (2016)
a MP sin
the star+disk,
CI Tau’sapparent magnitude of 7.793 in the K−1
7.0
pendent K
massesare needed. Several planets have been found 77.4candidatearound it with
a 8.989 days(IGRINS)
period based on analysis
P (km s )9.4
Spectrographband fromtheTwo
Micron All-Sky
Survey (2MASS; Skrutskie
via directMimaging
around pre-main-sequence stars, including 11.6of 2.9
its RV variations.
BasedonK-bandan inclination
of2.5
∼44°
estimated
P (MJ)
2.7
•
Hand
(1.45
–
micron),some around T Tauri stars (e.g., Chauvin et al. 2004; Ireland
et al.
and thewe calculate
an absolutefrom imaging its
disk2006),(Guilloteau
et system’s
al. 2014), distance,
its total massis0.33
et al. 2011; Rameau et al. 2013), and their measured
R~45,000
8.17
in
the
K-band
for
CI
Tau
b.
magnitudeofMJ. If the planet formed via some
0.21“hot start” mechanism,
Note. Distance from M. Simon et al. 2019, (in preparation), based∼11
on Gaiamagnitudes
have been used to evaluate planet formation•
McDonald
Obs.
2.7m
its
expected
contrast
ratio
with
its
host star should be a
et al. 2018) and Bailer-Jones et al. (2018). Stellar mass, initially −3
theories (Brown(Marleau& Cumming 2014; Rajan et al. 2017).
based onLowellmodelsObs.
from4.3m
Spiegel & Burrows (2012),
measured by Guilloteau et al. (2014), is adjusted for distance few×10
and theHowever, for these systems, the planet mass estimates are
4.
Discussion
and Conclusions
and
thus
would
be
directly
detectable
spectroscopically.
If,planet’s mass.
• 大気吸収の補正、主星のスペクト
necessarily model-dependent as it is generally not possible tohowever, the planet formed via a “cold start” method, its
Weル線の差し引き
havebeanalyzed
spectraof CI Tau and founddetect the stellar reﬂex motion given the extreme mass ratios
best, a ratio
no current
contrast ratio would
likely∼10−5 at K-band
supportof the existence of CI Tau b,
and the large star-companion separations. With the exception of
6 a hot Jupiter with atechniques are strong
sensitive
to. 2.9
β Pic b (Snellen & Brown 2018; Dupuy et al. 2019),
mass of 11.6 2.7 MJ. We have directly detected CO in CI Tau
have created a bootstrap sample (Efron 1979) of N=10,000
conﬁrmation of these objects as planetary mass companions
b’s atmosphere. We have also estimated its magnitude in the Ksets of 40 spectra, randomly sampling with replacement
is not yetdata
possible.
2.band.
Observations
and Data
Analysis
These results
make
CI Tau b the youngest conﬁrmed

319 CO Detected in CI Tau b: Hot Start Implied by Planet Mass and MK
Flagg1 , Christopher M. Johns-Krull1,2, Larissa Noﬁ3,4, Joe Llama3 , L. Prato2,3, Kendall Sullivan5 , D. T. Jaﬀe5 , and#16 Laura
The Astrophysical
Flagg et al.
Gregory
Mace5 Journal Letters, 878:L37 (5pp), 2019 June 20
The AstrophysicalJournalLeiers,(5pp),
2019
The AstrophysicalJournalLetters, 878:L37
878:L37 (5pp),
2019 June
20 June 20

Flagg et al.

およそ５シグマ

Figure 1. Cross-correlation function signiﬁcance plotted as a function of planet velocity amplitude and systemic rastandard deviations above the mean for those parameters, peaking at 5.7σ.

Figure 1. Cross-correlation function signiﬁcance plotted as a function of planet velocity amplitude and systemic radial velocity. The signiﬁcance is the number of
Figure1. Cross-correlation
functionsigniﬁcanceplottedpeaking
as a functionof planet velocity amplitude and systemic radial velocity. The signiﬁcance is the number ofstandard
deviations
above the mean
for thoseparameters,
at 5.7σ.
standard deviations above the mean for those parameters, peaking at 5.7σ.

otherderivedresultuncertaintiesforfor
P and
other
derivedresult inin underestimatedunderestimated uncertainties
KPKandresult in underestimatedquantities. We plan to em
method to explore the seorbital parameters and ho
uncertainties, are affecte
measurements of the planthe data that we current
will search for addition
using four out of overwhile not all of the order
be detected within theseO ratio and put additiona(Öberg et al. 2011). In
templates at different t
estimate the planet’s tem

quantities.
We planplan
employthe
theMarkov
Markov
Chain
Monte
Carlo
Contrast
ra8oquantities. We
totoemploy
Chain
Monte
Carlo
methodexplore thethesensitivity
sensitivityofofourour
results
to theassumedmethod toto explore
results
to theassumed•orbital(Star+disk)/planet= we356(+94-69)
parameters
andhowhowthethequantities
quantities
wemeasure,orbitalparameters andmeasure,andandtheirtheiruncertainties, areresultin in
more
accurate
uncertainties,
are affected.
affected.This
Thisshould
shouldresultmoreaccurate→mK =ofofthe
8.17
mag
for
CI Tau bThis research was supmeasurements
planetmass
magnitude.
Second,using
measurementstheplanet(+0.33-0.21)
massandandmagnitude.
Second,
using
the
data
that
we
currently
have
between
1.4
and
2.5
μm,
we
data that we currently have between 1.4 and 2.5 μm, weFund grant from Rice•thewill 10searchMfor
additional
currently
onlyonly
Jでこれだけ明るい
will
searchforadditionalmolecules.
molecules.WeWearearecurrently
acknowledge partial susing four
four outofdata,
and andusing
out start形成シナリオ（Fig.
of overover 40
40orders
ordersofofspectroscopic
spectroscopic
data,
→hot
2）が有力
INSPIRE grant to RiceOO
is present,
it could
while notnot all
all of
HH
is present,
it could
whileof thetheorders
ordersareareuseful,useful,if if22
be detected within these data as well. This could
inform the C/
bedetected within these data as well. This could
inform the C/
O ratio and put additional limitations on how the planet formed
O
ratio
and
put
additional
limitations
on
how
the
planetformedFigure2. etAbsolute
K magnitude
vs. agea selectionof planetarymass(Öbergal. 2011).
In addition,
by forusing
model atmosphere(Öbergetal.
2011).
In
addition,
by
using
model
atmospherecompanions.
In
red
are
the
hot
start
tracksfrom
Spiegel&Burrows
templates at different temperatures, in future work we will(2012),
templates
atstartdifferent
in future
work companions
we willwhile
the cold
trackstemperaturearetemperatures,in blue. The
known
planetary-massestimatetheplanet’s
directly.

aroundthe theyoungest
starstemperatureappear consistent
with a hot start formation.
estimateplanet’s
directly.
Magnitudes
for
2MASS
J12073346-3932539,
HD 95086
b, 1RXSThis research was supported in part by a Faculty
Initiative
J160929.1210524
b, wasβ Picsupported
HIP 65426
andby
Eria51b are from
Chauvin
Thisgrant
researchin b,
part
Faculty
Initiative
Fund
from
Riceb,University.
C.M.J.-K.
would
like
to
et al. (2004), Lafrenière et al. (2008), Bonnefoy et al. (2011), Ireland et al.
acknowledge
from
the
NSF
through
an to
Fund
grant
Ricesupport
University.
would
like
(2011),De
Rosafrom
etpartialal. (2016),
Chauvinet al.C.M.J.-K.
(2017),
Rajan
et al. (2017),
and
INSPIRE
grant
to
Rice
University(grantAST-1461918),
as 42Backnowledge
partialsupport
from
the
NSF
throughan b
Dupuy et al. (2018), respectively. Magnitudes for FW Tau b and ROXs
well
as grant
partialsupportfrom NASAthrough grant as
INSPIRE
Rice
University(grant AST-1461918),
arefrom Kraus
et al.to(2014).
Figure 2. Absolute K magnitude vs. age for a selection of planetary masscompanions. In red are the hot start tracks from Spiegel & Burrows (2012),
Figure while
2. Absolute
K magnitude
vs.blue.
age Thefor knowna selectionof planetary
mass
the cold start
tracks are inplanetary-masscompanions
companions.
are the hot
tracksfrom Spiegel
Burrows(2012),
around Intheredyoungest
starsstart
appearconsistent
with a&hot
start formation.
while thecold start tracks
are in blue.
The known planetary-masscompanions
Magnitudes
for 2MASS
J12073346-3932539,
HD 95086
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The SPHERE view of the jet and the envelope of RY Tau

arXiv:1906.06910v1 [astro-ph.SR] 17 Jun 2019

319
#17

A. Garufi1 , L. Podio1 , F. Bacciotti1 , S. Antoniucci2 , A. Boccaletti3 , C. Codella1, 4 , C. Dougados4 , F. Ménard4 ,D. Mesa5 , M. Meyer6 , B. Nisini2 , H.M. Schmid7 , T. Stolker7 , J.L. Baudino8 , B. Biller9 , M. Bonavita9 ,4 , A. Cheetham11 , S. Desidera5 , V. D’Orazi5 , M. Feldt10 ,M. Bonnefoy
F. Cantalloube, G. Chauvin
The SPHERE
view4, ofthe jet 10andthe envelopeof RY Tau ⋆34
5
7 , A.M. Lagrange4 , M. Langlois12 , J. Lannier4 ,R.
Galicher,A.
Grandjean,R.
Gratton,J.
Hagelberg
A. Garuﬁ1, L. Podio1, F. Baccioq1, S. Antoniucci2, A. Boccaleq3, C. Codella1, 4, C. Dougados4, F. Ménard4, D. Mesa5, M. Meyer6,
13 , A.L. Maire14 , C. Perrot3, 15, 16 , E. Rickman11 , T. Schmidt3 , A. Vigan17 , A. Zurlo17, 18, 19 , A. Delboulbé4 ,C. Lazzoni
B. Nisini2,
H.M. Schmid7,
T. Stolker7, J.L. Baudino8, B. Biller9, M. Bonavita9, M. Bonnefoy4, F. Cantalloube10, G. Chauvin4, A.
17 , D. Fantinel5 , O. Möller-Nilsson10 , L. Weber11 , and J.-F. Sauvage17
D.
Le
Mignant
Cheetham11, S. Desidera5, V. D’Orazi5,
M. Feldt10, R. Galicher3, A. Grandjean4, R. Graion5, J. Hagelberg7, A.M. Lagrange4, M.
Langlois12, J. Lannier4, C. Lazzoni13, A.L. Maire14,
Perrot3,
Rickman11, T. Schmidt3, A. Vigan17, A. Zurlo17, 18, 19, A.
(AffiliationsC.canbe found15,
after16,
the E.
references)
Delboulbé4, D. Le Mignant17, D. Fan8nel5, O. Möller-Nilsson10,
L. Weber11, and J.-F. Sauvage17
Received -; accepted arXiv:1906.06910v1 [astro-ph.SR] 17 Jun 2019
ABSTRACT

Context. Jets are rarely associated with pre-main-sequence intermediate-mass stars. This contrasts with the frequent detection of jets in lower-mass

or younger stars. Optical and near-IR observations of jet-driving sources are often hindered by the presence of a natal envelope.
Aims. Jets around partly embedded sources are a useful diagnostic to constrain the geometry of the concealed protoplanetary disk. In fact, thejet-driving mechanisms are a↵ected by both spatial anisotropies and episodic variations at the (sub-)au scale from the star.
Methods. We obtained a rich set of high-contrast VLT/SPHERE observations from 0.6 µm to 2.2 µm of the young intermediate-mass star RY Tau.
Given the proximity to the Sun of this source, our images have the highest spatial resolution ever obtained for an atomic jet (down to ⇠4 au).
Results. Optical observations in polarized light show no sign of the protoplanetary disk detected by ALMA. Instead, we observed a di↵use signal
resembling a remnant envelope with an outflow cavity. The jet is detected in the H↵, [S ii] at 1.03 µm, He i at 1.08 µm, and [Fe ii] lines in the 1.25
µm and 1.64 µm. The jet appears to be wiggling and its radial width increasing with the distance is complementary to the shape of the outflow
cavity suggesting a strong jet/envelope interaction. Through the estimated tangential velocity (⇡ 100 km s 1 ), we revealed a possible connection
between the launching time of the jet sub-structures and the stellar activity of RY Tau.
Conclusions. RY Tau is at an intermediate stage toward the dispersal of the natal envelope. This source shows episodic increases of mass accretion/ejection similarly to other known intermediate-mass stars. The amount of observed jet wiggle is consistent with the presence of a precessing
disk warp or misaligned inner disk that would be induced by an unseen planetary/sub-stellar companion at sub-/few-au scales. The high disk massof RY Tau and of two other jet-driving intermediate-mass stars, HD163296 and MWC480, suggests that massive, full disks are more efficient atlaunching prominent jets.
Key words. stars: pre-main sequence – protoplanetary disks – ISM: individual object: RY Tau – ISM: jets and outflows

1. Introduction
The formation history of planets is tightly connected to theglobal evolution of protoplanetary disks. Our knowledge of thedisk morphology has greatly advanced in the last few years
thanks to the high-contrast and high-resolution imaging in boththe visible/near-IR (NIR) and the (sub-)mm o↵ered by new instruments like VLT/SPHERE, GPI, and ALMA. However, if on
one hand ALMA has also access to younger, embedded sources(see e.g., Sheehan & Eisner 2017), the optical/NIR imaging has
important limitations in this regard because of their much higher
extinction. In fact, the protoplanetary disk of well studied premain sequence (PMS) stars like e.g., HL Tau (Takami et al. 2007)
or DG Tau B (Podio et al. 2011) have not been imaged at shortwavelengths, and the whole sample of disks with available NIR
images is biased toward more evolved sources with no remnant
envelope (Garufi et al. 2018).

fraction of the protoplanetary disk lifetime. Given the importance of this element for the star formation process, it is crucial
to establish if the ejection of jets is a general phenomenon forforming stars of all masses and evolutionary stages. Jets are also
a useful diagnostic of the innermost disk regions being tightly
connected to the accretion processes and the star/disk interplay.
It is known that jets are almost ubiquitous in protostars (seee.g., Nisini et al. 2015). However, jets are often observed in
more evolved PMS stars, and in particular around the low-mass(. 1.5 M ) TTSs (e.g., Hartigan et al. 1995; Bacciotti et al.
2002). The observations of these stars are facilitated by their intrinsic abundance and by their long PMS timescale that allows
the direct imaging of their disk after their parent envelope isdissipated. These low-mass stars preserve their outer convective
zones until and beyond the zero-age main sequence (ZAMS),
and are thus accompanied by strong magnetic field. On the other
hand, intermediate-mass stars (1.5 5 M ) develops a radiative8

arXiv:1906.03522v1 [astro-ph.GA] 8 Jun 20193

INAF-Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047, Selargius (CA), Italy
Max-Planck-Institut für Radioastronomie (MPIfR), Auf dem Hügel 69, 53121 Bonn, Germany
5
Joint ALMA Observatory, Alonso de Córdova 3107, Vitacura, Santiago, Chile
6
NAOJ Chile Observatory, Alonso de Córdova 3788, Oficina 61B, Vitacura, Santiago, Chile,
7
Department of Astronomical Science, School of Physical Sciences, SOKENDAI (The Graduate University for Advanced Studies),
Mitaka, Tokyo 181-8588, Japan4319 Warm gas in protostellar ou4lows II. EHV jet and ou4lows from OMC-2/3 ⋆I. Go ́mez-Ruiz1, A. Gusdorf2, S. Leurini3, K. M. Menten4, S. Takahashi5,6,7, F. Wyrowski4, R. Gu ̈sten4#18 A.
Received ; accepted[astro-ph.GA] 8 Jun 2019arXiv:1906.03522v1
ABSTRACT

Context. OMC-2/3 is one of the nearest embedded cluster-forming region that includes intermediate-mass protostars at early stagesof evolution. A previous CO (3–2) mapping survey towards this region revealed outflow activity related to sources at diﬀerent evolutionary phases.
Aims. The present work aims to study the warm gas in the high-velocity emission from several outflows found in CO (3–2) emission
by previous observations, determine their physical conditions, and make comparison with previous results in low-mass star-forming
regions.
Methods. We use the CHAMP+ heterodyne array on the APEX telescope to map the CO (6–5) and CO (7–6) emission in the OMC-2
FIR 6 and OMC-3 MMS 1-6 regions, and to observe 13 CO (6–5) at selected positions. We analyze these data together with previous
CO (3–2) observations. In addition, we mapped the SiO (5–4) emission in OMC-2 FIR 6.
Results. The CO (6–5) emission was detected in most of the outflow lobes in the mapped regions, while the CO (7–6) was foundmostly from the OMC-3 outflows. In the OMC-3 MMS 5 outflow, a previously undetected extremely high velocity gas was found in
CO (6–5). This extremely high velocity emission arises from the regions close to the central object MMS 5. Radiative transfer models
revealed that the high-velocity gas from MMS 5 outflow consists of gas with nH2 =104 –105 cm−3 and T > 200 K, similar to what isobserved in young Class 0 low-mass protostars. For the other outflows, values of nH2 >104 cm−3 were found.
Conclusions. The physical conditions and kinematic properties of the young intermediate-mass outflows presented here are similar
to those found in outflows from Class 0 low-mass objects. Due to their excitation requirements, mid−J CO lines are good tracers of
extremely high velocity gas in young outflows likely related to jets.
Key words. star formation – ISM: Clouds – ISM: jets and outflows – shock waves – ISM: Individual objects (OMC-2/3)

1. Introduction
Intermediate-Mass (IM) protostars, i.e. protostars whose massis in the range from 2 to 8 M⊙ , provide crucial informationon the star formation process because they link the low- andhigh-mass star formation (e.g. Crimier et al. 2010). IM protostars share some properties of massive protostars, such as
their existence in clusters and their ability to ionize the surrounding gas. On the other hand, they present the advantagethat they are more numerous and therefore located at closer
distances (!1 kpc) than most of the massive star-forming regions. Therefore they could fill the gap between low- and highmass star formation studies. Despite their relevance, very little is known about the formation and early evolutionary stagesof IM protostars (e.g. class 0 type objects). Although somedetailed studies have been conducted in the last years (e.g.,⋆

Based on observations acquired with the Atacama Pathfinder

Beltrán 2015; Takahashi & Ho 2012; Takahashi et al. 2009,2006; van Kempen et al. 2012; Crimier et al. 2010; Beltrán et al.
2008; Fuente et al. 2007, 2001; Zapata et al. 2005, 2004), little
information is available, in particular, about outflows from class
0 type sources.
Observations have shown that outflows from IM protostars(hereafter IM outflows) share some characteristics of outflows
from low-mass protostars, such as the high collimation factor in early evolutionary phases (Beltrán et al. 2008). On theother hand, in general, IM outflows are intrinsically more energetic than those driven by low-mass sources (Beltrán et al. 2008;
Takahashi et al. 2008). The values of the outflow momentum
rate, Fout , are higher in IM protostars than in low-mass objects,
which may be an indication that IM young stellar objects (YSOs) 9
accrete material faster (higher accretion rate) than the low-massones (Beltrán et al. 2008).
Regarding their physical conditions, such as kinetic tem-S. Y. Haffert! !1*, A. J. Bohn! !1, J. de Boer1, I. A. G. Snellen1, J. Brinchmann1,2, J. H. Gir
319 Two
protoplanets
around5 the young star PDS 70
C.accre8ng
U. Keller!
!1 and R. Bacon#20

S. Y. Haﬀert 1*, A. J. Bohn 1, J. de Boer1, I. A. G. Snellen1, J. Brinchmann1,2, J. H. Girard 3,4, C. U. Keller 1 and R. Bacon5
2019NatAs.tmp..329H

Newly forming protoplanets are expected to create cavities
and substructures in young, gas-rich protoplanetary disks1–3,
but they are difficult to detect as they could be confusedwith disk features affected by advanced image analysis techniques4,5. Recently, a planet was discovered inside the gap of
the transitional disk of the T Tauri star PDS 706,7. Here, wereport on the detection of strong Hα emission from two distinct locations in the PDS 70 system, one corresponding to thepreviously discovered planet PDS 70 b, which confirms the earlier Hα detection8, and another located close to the outer edgeof the gap, coinciding with a previously identified bright dust
spot in the disk and with a small opening in a ring of molecular emission6,7,9. We identify this second Hα peak as a second
protoplanet in the PDS 70 system. The Hα emission spectraof both protoplanets indicate ongoing accretion onto the protoplanets10,11, which appear to be near a 2:1 mean motion resonance. Our observations show that adaptive-optics-assisted,medium-resolution integral field spectroscopy with MUSE12targeting accretion signatures will be a powerful way to trace
ongoing planet formation in transitional disks at different
stages of their evolution. Finding more young planetary systems in mean motion resonance would give credibility to theGrand Tack hypothesis in which Jupiter and Saturn migrated
in a resonance orbit during the early formation period of ourSolar System13.
PDS 70 (V* V1032 Cen) is a young T Tauri star at a distanceof 113.43 ± 0.52 pc (refs. 14,15) with a spectroscopically determined
age of 5.4 ± 1.0 Myr (ref. 7). Its protoplanetary disk was first dis-

The PDS 70 system was observed with th
12
Explorer
PDS 70 (MUSE) at the European South
Very
Large Cen)
Telescope (VLT) in the Las(V* V1032
Optics (LTAO) assisted narrow-field mod
若いT
Tau星
ing
night
of 20 June 2018. MUSE is an op
距離 113.43±0.52
pc
integralfield spectrographthat covers
質量 0.76power
M_sunranging from λ/Δλ = 1,7
resolving
光度
L_sun several important accretthered,0.36
targeting
年齢 5.4±1.0
including
Hα Myrat λ = 656.28 nm. We procea high-resolution spectral differential ima
in which a scaled, continuum-normalize
tracted from the data at each spatial pixel
ther residuals in the spectrum of each sp
principle component analysis (see Methotion). HRSDI is only sensitive to sharp
spectral lines, because the continuum-no
all differential broadband features betwee
continuum light from starlight that is ref
PDS 70 and the continuum of potential pla
HRSDI we can side-step the common issu
contrast imaging techniques such as an(ADI) have, where the spatial informationreference. Such techniques are sensitive tosource and can generate artefacts that look
Using HRSDI we detecta strong Hα em
10locations in the PDS 70 system (Fig. 1), wition of PDS 70 b, and a second, 8σ sourcefrom the host star at a position angle of319 Two accre8ng protoplanets around the young star PDS 70
Y. Haﬀert 1*, A. J. Bohn 1, J. de Boer1, I. A. G. Snellen1, J. Brinchmann1,2, J. H. Girard 3,4, C. U. Keller 1 and R. Bacon5#20 S.2019NatAs.tmp..329H
NATURE ASTRONOMYLETTERSa
400
300∆DEC (mas)

200
100
0
–100
–200
–300
–400
–400 –300 –200 –100

0

100

200

300

400

∆RA (mas)

50–50.650 0.655 0.660
Wavelength (µm)

c

10
5
0
–5
0.650 0.655 0.660
Wavelength (µm)

d
SNR

10

SNR

SNR

b

10
5
0
–5
0.650 0.655 0.660
Wavelength (µm)

Fig. 1 | Overview of the PDS 70 system. a, The Hα detection map with anoverlay of the contours of the orbital radii and a white dot in the centre
that marks the position of the star. The contours for PDS 70 c are theminimum and maximum orbital radii found for the different wavelength
observations. For both objects the square apertures that were used forthe photometry are shown, with the red aperture for PDS 70 b and the
purple aperture for PDS 70 c. b–d, The corresponding spectra divided bytheir standard deviation are centred around the Hα line position. The four
apertures in orange (panel a) indicate reference areas that are used tocompare with PDS 70 c. The orange reference spectrum (panel c) does notshow any spectral feature, while both PDS 70 b and PDS 70 c (panels d andb, respectively) clearly show Hα in emission. DEC, declination; RA, rightascension; SNR, signal-to-noise ratio.

P Cygni profile with a blue-shifted emission and a red-shifted
absorption component, which is quite common and a sign of magnetospheric accretion21,22. The Hα line profile from PDS 70 b andlower temperature and mass or due to obscuration by dust from thedisk. Comparing
the K–L colour ofspectral
PDS 70 c to evolutionarymodelsHigh-resolu8on
diﬀeren8al
imaging (HRSDI)
indicates that the planet has a mass within the range of 4–12 MJ after
having included possible biases from the circumstellar disk andextinction (see Methods).
There is a high Radial
likelihoodvel.
that the estiH_alpha
FWHM
Line
mated mass of the companion, even by including some of the biases,
lineother structures[km/s][km/s]
proﬁleis overestimated due to possiblearound the planet(Fig. 3) such as additional scattered starlight, a circumplanetary disk
or potential streamers thatconnect
the circumstellar
PDS
70 athe planet0 to(def.)
147±5
P-Cyg
disk. Detailed hydrodynamical modelling of the system may put abetter constraint on the planet masses.
PDS 70 b25±8123±13
simpleWe estimated the mass accretion rates of both companions using
an empirical relation between the Hα 10% width, which is the fullPDS 7030±9 rate10,11. The
102±19simplewidth at 10% of the maximum,and cthe mass accretion
derived 10% widths are 224 ± 24 km s−1 and 186 ± 35 km s−1 for planets b and c, which indicate a mass accretion rate of 2 × 10−8±0.4 MJ yr−1
−1
70Mb：conﬁrma8onfor b and 1PDS
× 10−8±0.4
J yr for c. The combined mass accretion ratesof the planetsarecomparable
to the stellar accretion rate, which is• accre8on中の惑星
5.5 × 10−8±0.4 MJ yr−1. A previous estimate of the accretion rate of8planet b, •basedKeppler+18,
on the Hα luminosity, estimated themass accreMüller+18,
Wagner+18−8±1−1
tion of PDS 70 b to be 1 × 10 MJ yr . The estimate of ref. 8 basedon the absolute Hα luminosity needs to take the extinction into
account, which
as 3.0 magnitudes to include the effects
PDS was70 chosenc：新発見−第二の惑星
of a possible circumplanetary disk and the extinction by the circum• Their
輝線の特徴が主星（PDS
70accretiona）と異なるstellar disk.
measurement is consistent with the low
rate found here,→主星の散乱光ではない
which is not affected by extinction as it is based on
the width of the Hα line instead of the luminosity. At the current
accretion•rate, itMul8-epoch
would take 50–100astrometry（次ページ）
Myr to form Jupiter-mass planets, which is much longer than the typical disk lifetime of 10 Myr.
→主星の固有運動＋円盤の回転方向に運動
The accretion rates
of young stars are significantly decreasing near
the end of
theirformation
they detc8on
exhibit episodic accretion• K-L color,when
H nonbursts23. A similar scenario of long-term variable accretion might→bより赤い、進化モデルとの比較から4-12
M_J
apply to the planetsin this system. Short-term variability is due tothe accreting gas dynamics, which for example could be a rotating
hotspot on the planet surface or an orbiting accretion funnel fromthe circumplanetary
disk.
Mass accre8on
rates
Based on the wide gap in the disk and the low accretion rate of• 70H_alphaの線幅より（経験則）
the star, PDS
was already predicted to contain a multi-planet-8±0.4system18 where→b:
the planets
theM_J/yr,
mass flow c:
towards
star. M_J/yr
2x10block
1x10the-8±0.4
Hydrodynamical modelling of viscous disks suggests that a single,• M_J
Myr（diskの寿命~10Myrより長い）
massive planet
is only の惑星を作るのに50-100
able to open a small gap (<15 au)1,2. In contrast, multi-planet
systemsarethought
to
be
able
to
carve
large
→惑星形成末期でaccre8on rateが下がっているのでは 11
gaps in disks with azimuthal asymmetries2,3, where the gap width
is governed by the dynamical and viscous timescales of the disk.
Detailed hydrodynamical modelling will be necessary to constrain
the disk–planet interaction of the PDS 70 system. Another indication of a planet at a larger orbital distance came from the 870-μm

PDS 70 b

1 June 2016

NACO

L’

6.9!±!0.25

PDS 70 b

20 June 2018 MUSE

Hα

6.9!±!0.1

PDS 70 c

14 May 2016

K1

8.8!±!0.2

SPHERE

319 Two accre8ng protoplanets around the young star
PDS
70
PDS 70c
1 June 2016
NACO
L’
6.6!±!0.2
Y. Haﬀert 1*, A. J. Bohn 1, J. de Boer1, I. A. G. Snellen1, J. Brinchmann1,2,
J. H.
3,4, 2018
C. U. Keller
R. Bacon5
PDS 70c Girard
20 June
MUSE 1 and Hα
7.7!±!0.2#20 S.2019NatAs.tmp..329H
NATURE ASTRONOMYLETTERS

1.0

Hα 20 June 2018

300

b
400
300

0.8

200

c
400

0.8

100

0.6

0
0.4

–100
–200

0.6

0

0.4

–100
–200

0.2

–300
–400

0.0
–400

–200
0
200
∆RA (mas)

–400

0.0
–400

0
200
–200
∆RA (mas)

400

–16

–1

1.9!±!0.32

400
0.4

–100

0.2

–300
–400

0.0
–400

–200
0
200
∆RA (mas)

400

Fig. 2 | Multi-epoch detection of PDS 70 b and c. a, The Hα detection map of PDS 70 after removal of all direct and scattered starlight. PDS 70 b and chave their positions marked with white circles. The white star in the middle shows the position of the star. The feature just south of PDS 70 b is most likely
caused by image slicing in MUSE, as the signal is perfectly aligned with the slicing and field splitting axis and we do not see it in the other datasets. b, The
K1-band observations of PDS 70 with SPHERE/IRDIS after ADI processing. Both companions, with their positions marked by the white circles, are recoveredin the data. The position of the star is marked by the white star. c, NACO observations in the L-band. PDS 70 b is clearly visible, while PDS 70 c is connectedto the disk. This is due to the large FWHM of the point-spread function in the L-band. The disk should be a smooth ring according to previous research, theextension at the position of PDS 70 c is therefore most likely due to the planet itself. The position of the star is marked by the white star.

PDS
Table 1 |70
The photometry and astrometry of PDS 70 b and c•Component
Wideaccre8on
Dategap, 中心星のlow
Instrument Band ΔM (mag)Line flux (1rate
× 10
Position angle (°)
erg s cm )→mul8-planet
systemを持つと予想されていた
PDS 70 b
14 May 2016 SPHERE
K1
8.0!±!0.2
152.4!±!1.5

28

0.6

0
–200

0.2

–300

400

100

200
0
–200
–400
–600
–600 –400 –200

0

200

400

600

∆RA (mas)
Separation (mas)Orbital radius (au)–2

Fig. 3 | Composite image of the protoplanetary disk and the twocompanions. The disk image from SPHERE H-band observations is overlaid
PDS 70 b
1 June 2016
NACO
L’
6.9!±!0.25
151.4!±!2.0
181.2!±!10
22.2!±!3
PDS 70 b
20 June 2018 MUSE
Hα
6.9!±!0.1
3.9!±!0.37
146.8!±!8.5
176.8!±!25
21.0!±!3 with the white contours of the Hα emission of the two planets to indicate
円盤中の幅広いギャップとmul8-planet
systemPDS 70 c
14 May 2016 SPHERE
K1
8.8!±!0.2
285!±!1.5
215.1!±!7
33.6!±!1.5
their positions in the disk. The contours mark the 0.8, 0.5 and 0.3 level
PDS 70 c
1 June 2016
NACO
L’
6.6!±!0.2
283.3!±!2
254.1!±!10
39.7!±!4.5
with respect to the peak of the point source. The disk features a smooth• 単一の大質量惑星では狭い（<15au）ギャップしか作れない
PDS 70 c
20 June 2018 MUSE
Hα
7.7!±!0.2
1.9!±!0.32
277.0!±!6.5
235.5!±!25
38.6!±!4.5
outer disk and a perturbed inner disk. The darker features around the inner• Mul8-planet systemでは幅広いギャップが可能と予想される
disk are due to over-subtraction of the inner disk by the post-processing（幅はdynamical and viscous 8mescalesof themost massive
planet diskで決まる）
Jupiter was formed first and wasalgorithm.
migrating The planets are clearing out the large gap between the outer andtowards the young Sun, the formation and subsequent faster inward
600
inner
disk edges, which can be seen in the scattered light image. The outer• 軌道半径b: 20.6±1.2 au, c: 34.5±2
au
migration of Saturn locked the two planets in a 3:2 mean motion
planetis partially obscured by the outer disk.
resonance.
Thisisthoughttohavereversed
their,
now
coupled,400
186.13!±!7

21.3!±!1∆DEC (mas)→円軌道とすると平均運動が2:1の共鳴軌道に近い
migration direction outward towards their current orbits. Finding
other systems, likePDS 70, in mean motion resonance lends cred（太陽系の木星と土星の軌道進化「Grand
Track仮説」を示唆）
ibility to this formation scenario for our Solar System.
2000

NATURE ASTRONOMY | www.nature.com/natureastronomy
The observations with MUSE show that adaptive-opticsassisted, medium-resolution, integral field spectrographs are highly
efficient instruments to observe accretion emission spectra fromplanets in formation. We suspect that more accreting planets could
be found and characterized in transition disks with this technique.
Another exciting opportunity, which is now possible due to thehigh efficiency of both the HRSDI data processing technique andMUSE, is the detailed investigation of accretion on short andlong timescales. This will shed light on the variability of planetary
accretion and will lead to a better understanding of the formation of planets, allowing us to infer the formation history of the

MUSE+HRSDIは、原始惑星の強力な観測手段だ！
–200
–400
–600
–600 –400 –200

0200

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400

600

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Lp 1 June 2016

300

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∆DEC (mas)∆DEC (mas)1.0

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1

Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
e-mail: keppler@mpia.de
2
Department of Astronomy, University of Michigan, 311 West Hall, 1085 S. University Avenue, Ann Arbor, MI 48109, USA
3
Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road, NW, Washington,
DC 20015, USA
4
Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile
S. Y. Haﬀert
1*, A.Mixta
J. Bohn1, J. de Boer1,
I. A. G. Snellen1,
J. Brinchmann1,2,
J. H. Girard
3,4, C. U.deKeller
1 and R.
Bacon5 de
5UnidadInternacional
Franco-Chilenade Astronomía(CNRS, UMI 3386),
Departamento
Astronomía,
Universidad
2019NatAs.tmp..329H
Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile
6
Université Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
7
Institut
Radioastronomie
Millimétrique (IRAM), 300 rue de la Piscine, 38406 Saint Martin d’Hères, France
A&A de625,
A118 (2019)
8
Laboratoired’astrophysiquede Bordeaux, Université Bordeaux, CNRS, B18N, allee Geoffroy Saint-Hilaire,https://doi.org/10.1051/0004-6361/201935034&
33615
Pessac,France© M. Keppler et al. 20199
Department of Astronomy/Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
10
Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822, USA
11
European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
12
Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
13
LeidenHighly
Observatory,structured
Leiden University, PO
Box 9513,
2300 RAthe
Leiden,The Netherlands
diskaroundplanethost PDS 70 revealed
14
Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 OHA, UK
15
Purple Mountainby
Observatory& Key Laboratory
for Radio Astronomy,
Chinese Academy ofwith
Sciences,ALMA
2 West Beijing Road,
high-angularresolution
observations
Nanjing 210008, PR China
16
1
2 Maximilian
1
1 Germany 7,8
Departmentof Chemistry,
LudwigMunich,M. Keppler, R. Teague, J. Bae3 , M. University,
Benisty4,5,6Butenandtstr.
, T. Henning5-13,, R. 81377
van Boekel, E. Chapillon , P. Pinilla9 ,319 Two accre8ng protoplanets around the young star PDS 70#20

Astronomy
Astrophysics

参考
ALMA obs.
Band 770 mas (8 au)
Williams10 , G. H.-M. Bertrang1 , S. Facchini11 , M. Flock1 , Ch. Ginski12,13 , A. Juhasz14 , H. Klahr1 , Y. Liu15,1 ,Keppler+19 ReceivedJ. 8P.January
2019 / Accepted
20 February 2019
A. Müller1 , L. M. Pérez4 , A. Pohl1 , G. Rosotti13 , M. Samland1 , and D. Semenov1,16

ABSTRACTMax Planck Institute for Astronomy, Königstuhl 17, 69117
Heidelberg, Germany
e-mail: keppler@mpia.de
2
Context. Imaged
in theofgap
of a transition
and founda separation
about 195mas (⇠22au) from
its host
Department
Astronomy,
Universitydiskof Michigan,
311 atWest
Hall, 1085 S.ofUniversity
Avenue,Ann Arbor,
MI 48109,
USAstar at a position3
Departmentof Terrestrial
Magnetism,
Carnegiedetected
Institutionyoung
for Science,
5241
Road, NW,
Washington,angle of about
155 , PDS
70 b is themost robustly
planetto Broad
date. BranchThis systemis therefore
a unique laboratory for
DCthe
20015,USA of young planetary systems at the stage of their formation.
characterizing
properties
4
Departamentode Astronomía,
Universidad
Observatorio
1515,emission
Las Condes,
Santiago,
Chile
Aims. We 5aim
to trace direct
and indirect
imprintsdeofChile,
PDSCamino
70 b onElthegas and dustof thecircumstellar
disk in order to study
Unidad Mixta Internacional Franco-Chilena de Astronomía (CNRS, UMI 3386), Departamento de Astronomía, Universidad dethe properties
of
this
⇠5
Myr
young
planetarysystem.
Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile
Methods. 6We
obtained
ALMA
bandCNRS,
7 observations
PDS 70France
in dust continuum and 12 CO (3–2) and combined them with archival
Université
Grenoble
Alpes,
IPAG, 38000ofGrenoble,
7
data. This resulted
in Radioastronomie
an unprecedented
angular resolutionof rueaboutmas (⇠8au).Saint Martin d’Hères, FranceInstitut deMillimétrique(IRAM), 300
de la70
Piscine,38406
8
Laboratoire
decircumplanetary
Bordeaux, Université
Bordeaux,
CNRS,
B18N, ofallee
Geoffroy
Saint-Hilaire,
Results. We
derive and’astrophysique
upper limit onmaterial
at thelocation
PDS
70 b of⇠0.01 M and find a highly structured0033615
Pessac,Francecircumstellar
disk
in
both
dust
and
gas.
The
outer
dust
ring
peaks
at
0.65
(74
au)
and
reveals
a possible second unresolved peak at
900 85721, USA
Departmentof Astronomy/Steward
Observatory,
The shows
Universityof Arizona,
North Cherry
Avenue, Tucson,
about 0.531000 (60au). The
integrated intensityof CO also
evidenceof a933
depletionof emission
at ⇠0.2AZ(23 au) with a width of
Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822, USA
00
00⇠0.1 (11 au).
Thegaskinematics
show
evidenceofadeviation
fromKeplerianrotation
inside
.0.8
(91
au).
This implies a pressure
11
European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
gradient thatcanaccountforthelocation
of
the
dust
ring
well
beyondthelocation
of
PDS
70
b.
Fartherin,
wedetect an inner disk
12
Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
13 to be connected to the outer disk by a possible bridge feature in the northwest region in both gas and dust. We comparethat appears
Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
14
the observations
to ofhydrodynamical
simulations
that include
a planetwith different
that cover the estimated mass range that
Institute
Astronomy, Universityof Cambridge,
Madingley
Road, Cambridge,
CB3 masses
OHA, UK
15
PurpleMountainObservatory& Keyphotometry
Laboratory forRadioM
Astronomy,
Sciences,
BeijingRoad,
was previously
derivedfromnear-infrared(⇠5–9
find thatAcademy
even a ofplanetwith2 Westa massof 10
MJup may not be
Jup ). We Chinese
Nanjing
210008,PR China
sufficient to
explaintheextent
of
the
wide
gap,
and
an
additional
low-masscompanionmaybeneededtoaccountforthe observed disk
16
Department of Chemistry, Ludwig Maximilian University, Butenandtstr. 5-13, 81377 Munich, Germany
1morphology.

Received 8 January 2019 / Accepted 20 February 2019

Key words. stars: individual: PDS 70 – techniques: interferometric – hydrodynamics – planet-disk interactions –protoplanetary disks

ABSTRACT

13
Context. Imaged in the gap of a transition disk and found at a separation
195 masof(⇠22au) from
its hostsystem.
star at a Although
position
early ofin about
the history
a youngstellarthese sub1. Introduction
angle of about 155 , PDS 70 b is the most robustly detected youngstructuresplanet to date.
systemis therefore asa unique
areThisoften
interpreted
directlaboratory
imprintsforof planet–diskcharacterizing the properties of young planetary systems at the stage of their formation.
In recent years,
highWeangularresolution
observations
protointeractions,
it is still
to inunderstandAims.
aim to trace
direct and indirect
imprints ofof
PDS
70 b on thegas and dust emissionof thechallenging
circumstellar diskorder to studyand constrain
planetary disksthehave
revolutionizedview
of diskevolution the architectures of planetary systems that are needed to accountpropertiesof this ⇠5 Myrour
young
planetarysystem.

319 Two accre8ng protoplanets around the young star PDS 70
Y. Haﬀert 1*, A. J. Bohn 1, J. de Boer1, I. A. G. Snellen1, J. Brinchmann1,2, J. H. Girard 3,4, C. U. Keller 1 and R. Bacon5#20 S.2019NatAs.tmp..329H
M. Keppler et al.: PDS 70 ALMA observations
0

1

mJy beam
20

km s 1
30

40

0.0

1.5

0.4

0.5

0.5

Offset (arcsec)

1.0

0.0
0.5
1.0

1.2

1.6

0.0
0.5
1.0

1.5

1.5
1.5

1.0

0.5

0.0

0.5

1.0

1.5

1.5

1.0

Offset (arcsec)

0.0

0.5

1.0

(d)

0.5
spur

0.0

PDS 70b

Offset (arcsec)

shadowing

0.5

0.5

1.5

Offset (arcsec)

continuum absorption(c)Offset (arcsec)

1

(b)

1.0

0.5

mJy beam
0.8

1.5
(a)

Offset (arcsec)

ALMA obs.
Band 770 mas (8 au)
Keppler+19

10

peak

inner disk

0.0

spur
0.5
PDS 70b

0.5

0.0

0.5

Offset (arcsec)

0.5

0.0

0.5

Offset (arcsec)

Fig. 1. Observations of the 12 CO (left column) and the 350.6 GHz continuum (right column). Bottom row: closer view of the observations including
annotations where the color scaling has been stretched to bring out detail. The contours for the 12 CO are starting at 20% of the peak value to thepeak in steps of 10%. For the continuum, the gray dashed contour is 5 , and black contours start at 10 and increase in steps of 10 , where= 26 µJy beam 1 . The synthesized beams are shown in the bottom left corner of each panel.

with a brightness distribution that is slightly asymmetric in

3.1.1. Disk radial and azimuthal morphology

141

Laura Pérez

Department of Physics and Astronomy, Rice University, 6100 Main Street, MS-108, Houston, TX 77005, USA; isella@rice.edu
2
Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile
3
Unidad Mixta Internacional Franco-Chilena de Astronomía, CNRS, UMI 3386, Chile
4
Univ. Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France
5
Department of Astronomy, University of Michigan, 311 West Hall, 1085 South University Avenue, Ann Arbor, MI 48109, USA
6
Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road, NW, Washington, DC 20015, USA
7
Max Planck Institute for Astronomy, Königstuhl 17, D-69117, Heidelberg, Germany
8
European Southern
Observatory,Karl-Schwarzschild-Str.
2, D-85748
Garching,Stefano
GermanyFacchini8 , and Laura Pérez2
Andrea Isella1 , Myriam Benisty2,3,4, Richard
Teague5, Jaehan Bae6 , Miriam
Keppler7,
Received
2019
April
15;
revised
2019
June
12;
accepted
2019
June
14;
published
2019
July 11The Astrophysical Journal Leiers, 879:L25 (10pp), 2019 July 10

319 Detec8on of Con8nuum Submillimeter Emission Associated with Candidate#20 Protoplanets
Abstract

We present the discovery of a spatially unresolved source of submillimeter continuum emission (λ=855 μm)
associated with a young planet, PDS70c, recently detected in Hα emission around the 5Myr old T Tauri star
PDS 70. We interpret the emission as originating from a dusty circumplanetary disk with a dust mass between
2×10−3 M⊕ and 4.2×10−3 M⊕. Assuming a standard gas-to-dust ratio of 100, the ratio between the total massof the circumplanetary disk and the mass of the central planet would be between 10−4 and 10−5. Furthermore, wereport the discovery of another compact continuum source located 0 074±0 013 southwest of a second known
planet in this system, PDS70b, that was previously detected in near-infrared images. We speculate that the lattersource might trace dust orbiting in proximity of the planet, but more sensitive observations are required to unveil
its nature.
Key words: instrumentation: high angular resolution – instrumentation: interferometers – planetary systems –planet–disk interactions – planets and satellites: formation – protoplanetary disks
CPD might reach temperatures of thousands of Kelvin and emit
ALMA Band1.7 Introductionhydrogen recombination lines (e.g., Hα) and ultraviolet (UV)
Accordingcurrent theories, as the mass of a forming• toKeppler+2019とLong+2018のデータの再解析、キャリブレーションの改良
continuum emission (Zhu 2015; Marleau et al. 2017; Aoyama
planet increases
above ∼10(855Earthmicron)masses のみ(M⊕), the planet is• Con8nuum
et al. 2018).
expected to open a partially depleted gap in the circumstellar
To date, a few giant planet candidates still embedded in their
•
15m
to
6.9
km
→
0.025”
to
12”
(2.8
to
1360
au)
disk (Crida et al. 2006). Material ﬂowing through the gap thatparental circumstellar disks have been claimed (e.g., Kraus &enters the region where the gravity of the planet dominates overIreland 2012; Sallum et al. 2015; Reggiani et al. 2018), butthat of the改良点
host star (i.e., the planet Hill sphere) is trapped inmost still lack conﬁrmation. The most outstanding case is theorbit, forming
a rotating circumplanetary disk (CPD; Ward &• Self-calibra8on
PDS70 system, which comprises a ∼5 Myr old low-mass
Canup 2010).
In analogy with the star formation
process,• 2016年の観測で使ったgain
calibratorのﬂuxの誤りを修正(M = 0.76M:) T Tauri star at a distance of 113.4 pc (Müller
circumplanetary material is expected to lose angular momenet al. 2018, and references therein) surrounded by a disk with atum due to turbulence and viscosity, and accrete onto the planet
large inner cavity. A planetary-mass companion was detected
at a rate between 10−4 and 10−8 Jupiter masses (MJ) per year
within the cavity at multiple near-infrared (NIR) wavelengths
for a period of time comparable with the lifetime of the(1.0 μm<λ<3.8 μm) and at different epochs between 2012
circumstellar disk, i.e., a few Myr (Lubow & Martin 2012).
and 2018 (Keppler et al. 2018; Müller et al. 2018). This
Consequently, for a planet like Jupiter, more than 50% of its
companion, PDS 70 b, was also detected in the Hα line
mass might have passed through a CPD.
(λ=0.656 μm; Wagner et al. 2018), suggesting that it15is
In addition to regulating the ﬁnal mass of giant planets,
accreting gas. Recently, a second companion candidate, PDS
CPDs are the birthplace of satellites such as the main moons of
70 c, was discovered in Very Large Telescope/Multi Unit
Jupiter and Saturn. The density, temperature, and viscosity of a
Spectroscopic Explorer (VLT/MUSE) observations in the Hα319 Detec8on of Con8nuum Submillimeter Emission Associated with Candidate#20 Protoplanets

Andrea Isella1 , Myriam Benisty2,3,4 , Richard Teague5 , Jaehan Bae6 , Miriam Keppler7, Stefano Facchini8 , and Laura Pérez2
The AstrophysicalJournalLeiers,(10pp),
2019
The AstrophysicalJournalLetters, 879:L25
879:L25 (10pp),
2019 July
10 July 10
Isella et al.

Figure 1. ALMA images of the 855 μm continuum emission recorded toward the inner regions of the PDS70 circumstellar disk. The image on the left was obtained
adopting a robust parameter of 2 and has an angular resolution (FWHM of the synthesized beam) of 0 093×0 074 indicated by the black ellipse on the bottom left.
The image in the middle panel was created adopting a robust parameter of 0.3 and has an angular resolution of 0 067×0 050. White contours are drown at 3 and 5
times the rms noise level. See the text for the details. The labels PDS70bsmm and PDS70csmm indicate the compact sources of continuum emission discovered insidethe dust cavity. The image on the right shows an overlay between the VLT/Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) NIR image publishedin Müller et al. (2018), and the ALMA low-intensity red contours from the image with robust=2.0.

astrometry is measured relative to the stellar position. In order
to compare these measurements, we must therefore assume thatthe star is at the center of the disk.
The position of PDS 70 csmm is in agreement with the opticaland NIR position of PDS 70 c (see also Figures 1 and 8). At theestimated orbital radius 34.5 au, the orbital period of PDS 70 cshould be 230 yr, implying an angular yearly motion of about
0 008 in the clockwise direction, assuming a circular andcoplanar orbit. This is consistent with the shift observed
between 2016 and 2018. PDS 70 bsmm appears to be located16319 Detec8on of Con8nuum Submillimeter Emission Associated with Candidate#20 Figure
Protoplanets
1. ALMA images of the 855 μm continuum emission recorded toward the inner regions of the PDS70 circumstellar disk. The image on the left was obtained

adopting a robust parameter of 2 and has an angular resolution (FWHM of the synthesized beam) of 0 093×0 074 indicated by the black ellipse on the bottom left.
Andrea Isella1 , Myriam Benisty2,3,4 , Richard Teague5 , Jaehan Bae6 , Miriam Keppler7, Stefano Facchini8 , and Laura Pérez2
The image in the middle panel was created adopting a robust parameter of 0.3 and has an angular resolution of 0 067×0 050. White contours are drown at 3 and 5
PDS70ctimes
rms noise level. SeeJournal
the text for Leiers,
the details. The
labels PDS70b
ThetheAstrophysical
879:L25(10pp),
2019
Julysmm10indicate the compact sources of continuum emission discovered inside
smm andthe dust cavity. The image on the right shows an overlay between the VLT/Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) NIR image publishedin MüllerTheet al.
(2018), and theJournal
ALMA low-intensity
red contours
AstrophysicalLetters, 879:L25(10pp), from2019 theJulyimage
10 with robust=2.0.
Isella et al.

PDS 70 cの公転周期は230年Table 1
Adopted Parameters for PDS70b and PDS70c→公転による移動量は
8 mas/yr

astrometry is measured relative to the stellar position. In order
to compare these measurements, we must therefore assume thatstar is at the center of the disk.
Lp/Le
a/au
Name
Mp/MJ
M˙ (MJ yr-1the
)
(1)
(2)
(3)
(4)
(5)
The position of PDS 70 csmm is in agreement with the optical
20.6±1.2
2×10−8 and NIR position of PDS 70 c (see also Figures 1 and 8). At the
PDS70 b5–9
1.6×10−4
PDS70 c4–12
1.6×10−4
34.5±2.0
1×10−8 estimated orbital radius 34.5 au, the orbital period of PDS 70 cshould be 230 yr, implying an angular yearly motion of about
Note. Data from Wagner et al. (2018), Keppler et al. (2018), and Haffert et al.0 008 in the clockwise direction, assuming a circular and(2019).
coplanar orbit. This is consistent with the shift observed
between 2016 and 2018. PDS 70 bsmm appears to be locatedsouthwest of PDS 70 b at an angular distance of 0 074±
is spatially unresolved at the sensitivity and resolution of
0 013, as calculated by comparing the ALMA position withcurrent observations, strongly suggest that PDS 70 cmm traces
the closest NIR epoch (2018 February 24 from Müller et al.
warm dust emission from a CPD. This hypothesis is supported
2018). This offset, which is also visible in the overlay between
by the detection of Hα line emission attributed to accreting gas
ALMA and VLT/SPHERE observations shown in Figure 1,(Figure 8, Haffert et al. 2019). The planet itself would emit atsuggests that PDS 70 bsmm and PDS 70 b might have different
submillimeter wavelengths; however, we calculate that its
physical origins (see Section 4). Although the present analysis
855 μm ﬂux should be less than 0.1 μJy (assuming planet
has a caveat that the ALMA reference position might noteffective temperatures and radii as in Müller et al. 2018).
correspond to the position of the central star, a substantial offset
The spatially integrated ﬂux measured by ALMA can bewould be required to reconcile the difference and introducing
used to estimate the mass of the CPD. Following Isella et al.
such anFigure
offset3. would
leadshow
to athedisagreement
positionsof a CPD
Solid lines
dust mass andinouterradius of(2014), we assume that CPDs are vertically isothermal with a.
FutureALMA
observations
PDS
70
c
and
PDS
70
c
smm
characterized
by
855
μm
continuum
ﬂuxes
equal
to
that
measured
towardFigure 2.radial
Measured
astrometry for
PDS70band) ccontrolledwith 3σ errorbybars
the(seesum of
temperature
proﬁle(TCPD
c (106 μJy).theBlueinnermost
and red colors
correspondto CPD
capablePDS70of imaging
disk
regionsin models
greaterwhere theTable 2). The labels “smm cont” and “smm CO” refer to the position of theexternal irradiation frominternal viscous heating (Tacc) ofandwouldtheresultposition
in a CPDof
temperatureof 20 star
K and 80 K,
ALMA continuum sources relative to the center
the continuum emission anddetails stellar
mightirradiation
better alone
pinpoint
the central
Tirr,  ), so that
)
and
the
both
the
centralplanet(T
Vertical dashed lines are drawn at 0.3 times the Hill radius forirr,pthe center of the disk rotation as measured from thehost
CO starline (emission,
relativerespectively.
tothecircumstellar
material.
planet masses of 4MJ and 12MJ.
respectively.
4 Letters,4879:L254 (10pp), 2019
4
The
Astrophysical Journal
July 10Isella et al.
TCPD= Tacc + Tirr, p + Tirr,
(1 )
.

1
Estimating
the CPD Dust
For the3.2.
parametersof PDS70c,
Tacc Massvaries between one-third
We theassumea stellar
luminosity
L =0.36L
noted that
positionof theTable
ALMA
sourcesare relative(Müller
to the et al.
Adopted Parameters for PDS70b and åPDS70c e
PDC
70b（近赤外、H_alpha）とその近くに見えるサ
andone-seventhofT,suggestingthat
viscousirr,p position of PDS 70
center of
the 855
μmthe
continuum
emission and2018),
while
physical parameters
forCO
PDSkinematics
70 c (and b) are The agreement between theand its might
csmm heating
1
have
a
very
marginal
role.
˙
LpC.
/Lluminosity
a/au
Name
ブミリ波ピークPDC
70thatc_smmの関係は？
(MJ yrJ
eConversely,
as discussed
inp/M
Appendix
the optical
NIR)
counterpart, and the fact
the sub-mm emission
listed Min
Table
1. TheofPDS
70 c Mis andnotknown,
butoptical/NIR
(1)
(2)
(3)
(4)
(5)
From the CPD temperature derived using Equations (1)–(3),because the masses and ages of PDS 70 b and PDS 70 c are• the主星ー惑星系のL5にトラップされたダスト雲？
−4
andlower and upper limits of Tirr,å, we calculate the3
20.6±1.2
2×10−8
PDS70 bthought5–9
1.6×10weto be similar,
assumethat they mightalso have−4−8
expected
CPD70
continuum
emission at 855 μm using Equation
PDS70 c4–12
1.6×1034.5±2.0
1×10•PDC
bは実はjetの輝点を見ている？
similar luminosities.
(4) in Isella et al. (2014). To this end, we assume a CPD
The stellar irradiation at the position of PDS 70 c might
inclination equal to that of the circumstellar disk (i=51°. 7,
Note. Data from Wagner et al. (2018), Keppler et al. (2018), and Haffert et al.
dependon the geometry of the inner part of the circumstellar(2019).
Keppler et al. 2019), and a dust surface density proportional todisk, as this might occult the planets from direct stellar
r−1. Isella et al. (2014) showed that the slope of the surface
radiation, and on the amount of stellar light scattered by thedensity proﬁle has little effect on the total disk ﬂux. We assume
is spatiallyunresolved
sensitivity
anditself
resolutionof Turner
circumstellar
dust atringthetowardthe planet(see, e.g.,
an inner disk radius equal to the planet radius, which iscurrent etobservations,stronglysuggest2018).
that PDS
70 capproximation,al. 2012; Isella& Turner
In ﬁrsta
mm traces
estimated to be about 3 Jupiter radii based on the planet
warm dust
emissiona CPD.
This correspondhypothesis istosupported
the midplane
lower
limit fromof Tirr, mighttemperature and luminosity, and a dust opacity of 3.5 cm2 g−1
by the detectionof Hα
lineopticallyemissionthickattributed
to accreting
temperatureof ancircumstellar
disk,gas
where all17

319 Detec8on of Con8nuum Submillimeter Emission Associated with Candidate#20 Protoplanets

Andrea Isella1 , Myriam Benisty2,3,4 , Richard Teague5 , Jaehan Bae6 , Miriam Keppler7, Stefano Facchini8 , and Laura Pérez2
The Astrophysical Journal Leiers, 879:L25 (10pp), 2019 July 10

The Astrophysical Journal Letters, 879:L25 (10pp), 2019 July 10

Isella et al.

Figure 6. Left panel: image of the 855 μm continuum emission recorded toward PDS70 and imaged with a robust parameter equal to 0.3, as in the central panel of
Figure 1. Middle panel: image of the symmetric component of the continuum emission calculated as discussed in Appendix B. Right panel: image of the residuals
obtained by subtracting the symmetric component of the emission (middle panel) from the observations (left panel). Dashed and solid contours correspond to ±3×the rms noise level (rms=19 μJy beam−1).
Table 2
Relative Astrometry of PDS70 b and c
Date

Instrument/Filter/λ0 (μm)

2012 Mar 31
2015 May 3
2015 May 31
2016 May 14

NICI/L′/3.78
SPHERE/H3/1.67
SPHERE/H2/1.59
SPHERE/K1/2.11

2016 Jun 1

NACO/L′/3.80

2018 Feb 24
2018 Jun 20

SPHERE/K1/2.11
MUSE/Hα/0.656

δR.A. (mas)δDecl. (mas)Sep. (mas)PA (deg)

References

Astrometry of PDS70 b
58.7±10.7−182.7±22.2
83.9±3.6−178.5±4.0
89.4±6.0−178.3±7.1
90.2±7.3−170.8±8.6
86.2±5.4−164.9±6.6
94.5±22.0−164.4±27.6
86.7±7.3−159.1±9.3
109.6±7.9−157.7±7.9
96.8±25.9−147.9±25.4

191.9±21.4
197.2±4.0
199.5±6.9
193.2±8.3
186.1±7.0
189.6±26.3
181.2±10.0
192.1±7.9
176.8±25.0

162.2±3.7
154.9±1.1
153.4±1.8
152.2±2.3
152.4±1.5
150.6±7.1
151.4±2.0
147.0±2.4
146.8±8.5

Keppler et al. (2018)
Keppler et al. (2018)
Keppler et al. (2018)
Keppler et al. (2018)
Haffert et al. (2019)
Keppler et al. (2018)
Haffert et al. (2019)
Müller et al. (2018)
Haffert et al. (2019)18

319 Detec8on of Con8nuum Submillimeter Emission Associated with Candidate#20 Protoplanets

Andrea Isella1 , Myriam Benisty2,3,4 , Richard Teague5 , Jaehan Bae6 , Miriam Keppler7, Stefano Facchini8 , and Laura Pérez2
The AstrophysicalJournalLetters, 879:L25
879:L25 (10pp),
2019 July
10 July 10
Isella et al.
The AstrophysicalJournalLeiers,(10pp),
2019

Figure 8. VLT/SPHERE NIR image (left panels; Müller et al. 2018) and VLT/MUSE Hα image (right panels; Haffert et al. 2019). The white contours are drawn at 3
and 5 times the rms noise level of the 855 μm continuum emission, imaged with robust=0.3 (top row) and robust=2 (bottom row). The signal located in thesouthwest of PDS 70 b in the VLT/MUSE image is likely due to instrumental artifacts (Haffert et al. 2019).

ORCID iDs

Isella, A., & Turner, N. J. 2018, ApJ, 860, 27
Keppler, M., Benisty, M., Müller, A., et al. 2018, A&A, 617, A44

193192019Intrinsic
elongatedporous dust grains
019 June 25. Received
June 17; in polariza8on
original form 2019of
June
6
Kirchschlager ,1‹ Gesa H.-M. Bertrang 2 and Mario Flock 2#21 Florian
MNRAS 488, 1211–1219 (2019)
ABSTRACT

Observations of the Atacama Large Millimeter Array (ALMA) revealed recently polarizedradiation of several protoplanetary discs in the (sub)millimetre wavelength range. Besides selfscattering of large particles, thermal emission by elongated grains is a potential source for thedetected polarization signal. We calculate the wavelength dependent absorption and intrinsic
polarization of spheroidally shaped, micrometre, and submillimetre sized dust grains using
the discrete dipole approximation. In particular, we analyse the impact of dust grain porositythat appears to be present in discs when small grains coagulate to form larger aggregates. For
the first time, our results show that (a) the intrinsic polarization decreases for increasing grain
porosity and (b) the polarization orientation flips by 90 deg for certain ratios of wavelength
to grain size. We present a new method to constrain grain porosity and the grain size inprotoplanetary discs using multiwavelength polarization observations in the far-infrared tomillimetre wavelengths. Finally, we find that moderate grain porosities (P ! 0.7) potentiallyexplain the observed polarization fraction in the system HD 142527 while highly porous grains(P > 0.7) fail unless the grain’s axis ratio is extraordinarily large.
Key words: polarization – interplanetary medium – circumstellar matter – stars: pre-mainsequence – dust, extinction – infrared: planetary systems.

ODUCTION

s in protoplanetary discs are responsible for the absorpcattering of both stellar and thermal radiation (in thehick regime). Besides the geometrical characteristics ofs, dust grain properties such as their size, composition,
ure are the decisive elements for the optical appearance

properties, and (if applicable) alignment mechanisms of asphericalgrains, and the interpretation of the polarized observations requires
sophisticated models (Cho & Lazarian 2007; Bertrang, Flock &Wolf 2017; Bertrang & Wolf 2017).
Accordingly, the origin of the detected polarization signals is
still highly debated. Besides dust scattering of anisotropic, thermalradiation of grains of size ∼ λ/(2 π) (Kataoka et al. 2015), dichroic

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20