Stefano Facchini, Andrea Isella, Miriam Keppler, Laura M. Pérez, and Richard Teague

partment of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road NW, Washington, DC 20015, USA; jbae@carnegiescience.edu
2
Department of Physics and Astronomy, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154, USA
3
IRAP, Université de Toulouse, CNRS, UPS, F-31400 Toulouse, France
4
Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile
idad Mixta Internacional Franco-Chilena de Astronomía (CNRS, UMI 3386), Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515,
Las Condes, Santiago, Chile
6
Univ. Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France
7
Zentrum für Astronomie,1,13
Heidelberg University, Albert Ueberle
2 Str. 2, D-69120 Heidelberg, Germany
3
4,5,6
7
8
European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching, Germany
9
10 USA
4
11,12
Department of Physics and Astronomy, 8Rice University, 6100 Main 9
Street, MS-108, Houston, TX 77005,
10
Max Planck Institute for Astronomy, Königstuhl 17, D-69117, Heidelberg, Germany
11 1 Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road NW, Washington, DC 20015, USA; jbae@carnegiescience.edu
Department of Astronomy, University of Michigan, 311 West Hall, 1085 S. University Avenue, Ann Arbor, MI 48109, USA
12
2
Harvard-Smithsonian
for Astrophysics,
60 GardenUniversity
Street, Cambridge,
MA 02138,
Department ofCenter
Physics
and Astronomy,of Nevada,
LasUSA
Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154, USA
Received 2019 August 20; revised 2019 September 18;3accepted 2019 September 20; published 2019 October 15
IRAP, Université de Toulouse, CNRS, UPS, F-31400 Toulouse, France
4
Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile
5
Abstract

An Ideal Testbed for Planet–Disk Interaction: Two Giant Protoplanets in ResonanceShaping the PDS 70 Protoplanetary Disk
Jaehan Bae, Zhaohuan Zhu , Clément Baruteau , Myriam Benisty
Stefano Facchini , Andrea Isella , Miriam Keppler, Laura M. Pérez, Cornelis P. Dullemond, and Richard Teague,

背景
Unidad Mixta Internacional Franco-Chilena de Astronomía (CNRS, UMI 3386), Departamento de Astronomía,
Universidad de Chile, Camino El Observatorio 1515,- 原始惑星系円盤で形成中の惑星を見つけれ
While numerical simulations have been playing a key role in the studies Lasof planet–diskinteraction,
testing
Condes, Santiago,
Chilenumerical results against observations has been limited 6so
far. Grenoble
With the Alpes,
two directly
protoplanets
Univ.
CNRS, imaged
IPAG, F-38000
Grenoble,ば観測的に重要
France7
embedded in its circumstellar disk, PDS70
offers füran ideal
testbed forplanet–diskinteractionAlbertstudies.
Using Str.
two-2, D-69120 Heidelberg, Germany
Zentrum
Astronomie,
Heidelberg
University,
Ueberle8
原始惑星系円盤PDS70は中心に大きなdimensional hydrodynamic simulations we showthat the Southernobserved Observatory,
features can bewell explained with the2,two
EuropeanKarl-Schwarzschild-Str.
D-85748-Garching,
Germany
9planets in formation, providing strong
evidence that
previously
theories
planet–disk6100
interaction
in MS-108, Houston, TX 77005, USA
Departmentof Physics
andproposed
Astronomy,
RiceofUniversity,
Main areStreet,cavityを持つ天体
10
action, including resonant migration, particle trapping,size
segregation,
andﬁltration.
Our
simulations
suggestthat
Max Planck Institute for Astronomy, Königstuhl 17, D-69117, Heidelberg, Germany
the two planets are likely 11
in 2:1 mean motion resonance and can remain dynamically stable over million-year
Department of Astronomy,
Universityof Michigan, 311 West Hall, 1085 S. University-Avenue,
Ann Arbor, MI 48109, USA
cavityの中にHα線などで点源が２つ見つ−8−7−1
timescales. The growth of the planets at1210 –10 MJupyr , rates comparable to the estimates from HαHarvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
observations, does not destabilize the resonant conﬁguration. Large grains are ﬁltered at the gap edge and only
かった。これは、原始惑星への降着を示
Received
2019
August20;
revised2019
September
18;
accepted
2019
September
20;
published 2019 October 15
small, (sub-)μm grains can ﬂow to the circumplanetary disks (CPDs) and the inner circumstellar disk. With thesubmillimeter continuum ring observed outward of the two directly imaged planets, PDS70 provides the ﬁrst
しているだろう(PDS70b,c)observational evidence of particle ﬁltration by gap-opening planets. The observed Abstract
submillimeter continuum
emission at the vicinity of the planets can be reproduced when (sub-)μm grains survive over multiple CPD gas- もし惑星が理由で円盤にcavityができてviscous timescales andaccumulate
therein. simulations
One such possibility
if (sub-)μm
grainsa growsize andremainWhile
numerical
have isbeen
playing
key inrole
in thestudies ofいるとしたら、それはシミュレーション
planet–disk interaction, testing
trapped in pressurenumericalbumps, similar
to whatagainst
we ﬁnd observations
happening in circumstellar
We discuss
potential
results
has beendisks.
limitedso far.
With the two directly imaged protoplanets
implications to planet formation in the solar system and mature extrasolar planetary systems.
とあっているだろうか？
embedded in its circumstellar disk, PDS70 offers an ideal testbed for planet–diskinteraction studies. Using twoUniﬁed Astronomy Thesaurus concepts: Circumstellar disks (235); Planet formation (1241); Hydrodynamical
simulations (767) dimensional hydrodynamic simulations we show that the observed features can be well explained with the twoplanets in formation, providing strong evidence that previously proposed theories of planet–disk interaction are in→円盤の中に惑星を2つ置くシミュレーショ
action, including resonant migration, particle trapping, size segregation, and ﬁltration. Our simulations suggest thatinteraction studies. The two planets, PDS70b and c, are located
1. Introduction
ンを行い、観測事実を再現できるか調べた
the two planets are likely in 2:1
mean
motionresonanceandcanremaindynamicallystable over million-year
195and234mas(Keppler
et
al.
2018;
Haffert
et
al.
2019)
from
Numerical simulations havetimescales.
been playing The
a key growthrole in theof the planets at 10−8–10−7M yr−1, rates comparable to the estimates from HαJupstar PDS70 (Müller et al.
the 5.4Myr old, K7 pre-main-sequenceies of planet–disk interaction and planet formation, by2018)theon thesky. The conﬁguration.
deprojected distances
betweenthe planetsdoes
not destabilize
resonantLargegrainsare ﬁltered at the gap edge and only
ﬁrming analytic theories, observations,
examining nonlinear
phenomena,and tothe thestar (∼20
and 35 au) suggestdisksthat the(CPDs)
two planets
are insmall, (sub-)μm grains can ﬂow
circumplanetary
andtheor inner circumstellar disk. With theAn Ideal Testbed for Planet–Disk Interaction: Two Giant Protoplanets in ResonanceShaping the PDS 70 Protoplanetary Disk
1,13

1

2

3

4,5,6

Jaehan Bae, Zhaohuan Zhu , Clément Baruteau , Myriam Benisty
89104
Stefano Facchini , Andrea Isella , Miriam Keppler, Laura M. Pérez

7, Cornelis P. Dullemond
11,12, and Richard Teague,

Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road NW, Washington, DC 20015, USA; jbae@carnegiescience.edu
2
Department of Physics and Astronomy, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154, USA
3
IRAP, Université de Toulouse, CNRS, UPS, F-31400 Toulouse, France
4
Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile
5
Unidad Mixta Internacional Franco-Chilena de Astronomía (CNRS, UMI 3386), Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515,
Las Condes, Santiago, Chile
6
Univ. Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France
7
Zentrum für Astronomie, Heidelberg University, Albert Ueberle Str. 2, D-69120 Heidelberg, Germany
8
European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching, Germany
9
Department of Physics and Astronomy, Rice University, 6100 Main Street, MS-108, Houston, TX 77005, USA
10
Max Planck Institute for Astronomy, Königstuhl 17, D-69117, Heidelberg, Germany
11
Department of Astronomy, University of Michigan, 311 West Hall, 1085 S. University Avenue, Ann Arbor, MI 48109, USA
12
Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
Received 2019 August 20; revised 2019 September 18; accepted 2019 September 20; published 2019 October 15

Abstract
While numerical simulations have been playing a key role in the studies of planet–disk interaction, testing
numerical results against observations has been limited so far. With the two directly imaged protoplanets
embedded in its circumstellar disk, PDS70 offers an ideal testbed for planet–disk interaction studies. Using twodimensional hydrodynamic simulations we show that the observed features can be well explained with the twoplanets in formation, providing strong evidence that previously proposed theories of planet–disk interaction are inaction, including resonant migration, particle trapping, size segregation, and ﬁltration. Our simulations suggest thatthe two planets are likely in 2:1 mean motion resonance and can remain dynamically stable over million-yeartimescales. The growth of the planets at 10−8–10−7MJupyr−1, rates comparable to the estimates from Hαobservations, does not destabilize the resonant conﬁguration. Large grains are ﬁltered at the gap edge and only
small, (sub-)μm grains can ﬂow to the circumplanetary disks (CPDs) and the inner circumstellar disk. With the

–100
–200
–300
–400

100

0.6

0

∆DEC (m00.6∆DEC (m∆DEC (m

100

100

0.6

0

An Ideal Testbed for Planet–Disk Interaction: Two Giant Protoplanets
in Resonance
2. ModelSetup
2.1. Initial Gas Disk
Shaping the PDS 70 Protoplanetary Disk
0.4

0.4

–100
–200

0.2

0.4

–100
–200

0.2

–300
–400

0.2

–300
–400

The0 AstrophysicalJournalLetters,
884:L41(12pp), 2019
October0 20200–400 –2000200
400–400 –200–400 –200
200
400
0.0

0.0

1,13

2

3

0.0
400

We adopt an initial disk gas surface7density proﬁle that falls
4,5,6

∆RA
(mas)
∆RA
(mas)
JaehanBae,
Zhaohuan
Zhu,
Clément
Baruteau,
MyriamBenisty,CornelisP.
Dullemond
,
off
with
an
exponential
tailagainstradiusR:
この研究：FARGO-3Dを走らせた
ほかは普通のセットアップ
8
9
10
4
11,12
suggestthatbothplanetsaresurrounded
by
a
dusty
circumpladensity-weighted,
verticallyintegrated
temperature T̄
StefanoFacchini,
AndreaIsella,MiriamKeppler
,
Laura
M.
Pérez
,
and
Richard
TeagueFig. 21| 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 c-1
PDS
70bの質量は5Mjに固定⎛⎞⎛ R⎞
Department
ofwithTerrestrial
Magnetism,
for
Science,5241
Broad
BranchNW, Washington, DC 20015, USA; jbae@carnegiescience.edu
Rnetarydisk(CPD;
Christiaens
etInstitution
al.the2019;etfeatureal. 2019),
while
have theirpositions marked
white circles.
The whitestar inCarnegie
the middle shows
positionof Isella
thestar. Thejust
south ofPDS 70 b Roadis most likely∆RA (mas)-⎟0.24
S
(
R
)
=
S
exp
,
(1 )
⎜
⎟
⎜
gas,initc⎛⎞R
caused by image slicing inDepartment
MUSE, as the signal
isperfectly alignedwith the slicing andfield splitting of
axisNevada,and we do not
seeVegas,
it in the otherdatasets.
b, TheofPhysics
andAstronomy,
University
Las
4505
South
Maryland
Parkway,
Las
Vegas,
NV
89154,
USA⎝ R cK⎠⎜⎝ ⎟Rc ⎠ .
thenatureof the5,10Mjを試した
submillimeter
detectednear
PDS70b,¯- PDS
70cの質量は2.5,
3 Bothemission
T
R
44
(
)
=
K1-bandobservationsof PDS 70
with
SPHERE/IRDIS
after
ADI
processing.
companions,
with
their
positionsmarkedbythewhitecircles,arerecovered
The Astrophysical Journal
Letters,
884:L41(12pp), 2019
October
B
IRAP,
Universitéde Toulouse,
CNRS,
UPS, 20
F-31400 Toulouse, France⎝⎠
4
in the data. The positionof the staris marked
by the whitestar. c, NACO
observationsin the L-band. PDS
70PDS70b
b is clearly visible,inferred
while PDS 70 c is connected
22 au
which
is
74masoffsetfromthelocationofDepartamentodeAstronomía,
Universidad
deChile,
CaminoEl
Observatorio
1515,
Las
Condes,Santiago,
Chile
初期軌道半径は20auと35au
to- thewhere we choose Rc=40 au and Σc=2.7gcm−2 so that the
5disk. 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, the
from
Hα/IR
emission,
isto theyet
tobesurrounded
explained(Isellaetal.white2019).
UnidadMixta
Internacional
Franco-ChilenadeAstronomía(CNRS,
UMI
Departamentode Astronomía,
Universidad de Chile,
Caminointegrated
El Observatorio
1515,
T̄
suggestthatplanets
arebya3386),
dusty
circumplais
density-weighted,
verticallytemperatureextensionat the positionof PDS70 c is therefore
mostbothlikely due
planetitself.
The
positionof the staris marked
by the
star.
total
disk
gas
mass
withinthesimulation
domainis0.003M,
Adopting a stellar mass of 0.85Me (Keppler et al.e 20(すなわち2:1軌道共鳴よりちょっと外にある)
Las
Condes,Santiago,
Chile
Interestingly
many
aforementioned
observed
netary disk enough,(CPD; Christiaens
al. 2019;
Isella et al. 2019),
while
6 ofetthesimilarto the model usedin Keppler
et al.⎞(2019).
0.24 temperature
Univ. Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble,
Francemolecularameanweight
of
2.4,
this
⎛
R
7 of thethenaturesubmillimeteremission
detectednear
PDS70b,
featureshave
been
previously
seen
in
and
proposedtohappen
¯
To
set
up
the
initialdisk
temperature⎟ proﬁle,. we iterate(R) = 44 K ⎜Zentrum
Germany
Table 1 | The photometry and astrometry of
PDS 70 b für
and cAstronomie, Heidelberg University, Albert Ueberle Str. 2, D-69120 Heidelberg, T
corresponds
to
a
disk
aspect
ratio
H/R
of
⎝
⎠
8
Monte
Carlo
radiative
transfer(MCRT)
calculations
using
22
au
which
is
74masoffsetfromthelocationofPDS70binferredin
protoplanetarydisks
bynumerical
simulations.
Multiple
EuropeanSouthern
Observatory,Karl-Schwarzschild-Str.
2,
D-85748
Garching,
Germany
Component Date
Instrument Band ΔM (mag) Line flux (1 × 10
Position angle (°)
Separation (mas)Orbital radius (au)9
RADMC-3D(Dullemondet al. 2012) until
we obtain a
erg
s
cm
)
DepartmentofPhysics
andAstronomy,
Rice
University,
6100
Main
Street,MS-108,
Houston,TX
77005,
USA
from
Hα/IR
emission,
is
yet
to
be
explained(Isellaetal.
2019).
0.38
planets in resonance 10are proposed as a possible cause of inner⎛⎞R
Adoptingastellarmassof0.85M(Keppleretal.
201
converged
three-dimensional
disk
densityandtemperatureeMax
PlanckInstitutefor
Astronomy,
Königstuhl
17,
D-69117,
Heidelberg,
Germany
PDS 70 b
14 May 2016 SPHERE
K1
8.0!±!0.2
186.13!±!7
21.3!±!1⎜⎟
enough, manydisksof152.4!±!1.5
theaforementioned
observed
H RA).=The
0.067. ﬁt to the
11 Interestingly
cavitiesseenin(pre)transitional
(Zhu
et
al.
2011).
Inthe
proﬁle(see
Appendix
least-squares
power-lawa meanweight2.4,
thistemperature
Department
Astronomy, University ofMichigan, 311
West Hall, 1085
S. University
Avenue,molecular
Ann Arbor, MI
48109, ofUSA
PDS 70 b
1 June 2016
NACO
L’ of 6.9!±!0.25
151.4!±!2.0
181.2!±!10
22.2!±!3⎝⎠22
aufeatureshave
previously
seen
in
and
proposedtohappen
12 been beyondpressurebumpformingaplanet’s
orbit,
particles
canbeStreet, Cambridge,
Harvard-Smithsonian
Centerfor Astrophysics,
MA 02138,
USA
PDS 70 b
20 June 2018 MUSE
Hα
6.9!±!0.1
3.9!±!0.37
146.8!±!8.5
176.8!±!25 60 Garden
21.0!±!3
corresponds
toadisk aspect ratio H/R of2inprotoplanetarydisks
bynumerical
simulations.
Multiple
2019
Augustrevisedsegregation
2019 September215.1!±!7
accepted
2019 September 20; published 2019 October 15
PDS 70 c
14 May2016 SPHERE Received
K1
8.8!±!0.2
285!±!1.5
33.6!±!1.5
efﬁciently
trapped,andwe 20;
expectof18;grain
sizes
2

–16

–1

–2

0.38
NACO
L’ resonance
6.6!±!0.2
283.3!±!2
254.1!±!10
39.7!±!4.5
planets
inareproposedasapossible
cause
of
inner
⎛
⎞
R
2.2.
Planets
such
that,
under
typicalprotoplanetarydisk
conditions,
smaller⎜⎟
PDS 70 c
20 June 2018 cavities
MUSE
Hα
7.7!±!0.2
1.9!±!0.32
277.0!±!6.5(Zhu et235.5!±!25
38.6!±!4.5
H
R
=
0.067
.
seen
in (pre)transitional
disks
al.
2011).
Inthe⎝ 22 au ⎠grains are distributed over a larger radial extent, Abstract
resulting in a
We ﬁx PDS 70b’s mass to 5 MJup, consistent withpressure bump forming beyond a planet’s orbit, particles can besmallercavity size
(Pinilla
et
al.
2012;
Zhu
et
al.
2012).
The
Whileefﬁciently
numerical
simulations
have
been
playing
a
key
role
in
themigrating
studiesofplanet–diskinteraction,
testing
most
massiveplanetJupiterwasformedfirstwastrapped, and we expect segregation of grain andsizes
estimates(Keppler
et
al.
2018;
Mülleretal.
2018).
towards
the youngSun,
the formationand subsequent
fasterinwardthe two directly imaged protoplanets
numerical
results
againstobservations
has
been
limited
so
far.
With
edge
of
the
gap
can
act
as
a
ﬁlter
so
small
particlescan
600 outer
2.2.
Planets
such
that,
under
typicalprotoplanetarydisk
conditions,
smallerthreedifferent
masses
for
PDS
70c:
2.5,
5,
and
10
M
migrationofSaturnlockedthetwoplanets
in
a
3:2
mean
motion- 2Myr 動かした。その間、惑星の質量を10^4年かembeddedinits
circumstellar
disk,
PDS70offersanideal
testbedforplanet–diskinteraction
studies.
Using
twopenetratetheplanet-induced
gap,
whereaslarge
particlesareresonance.
Thisisthoughttohavereversed
their,
now
coupled,400
grains are distributed over a larger radial extent, resulting in a
twoWe
planets
are initiallyplacedatM20
and35au,
inanag
migration
direction
outwardtowards
theircurrent
orbits.
Finding,
consistent
with
pr
ﬁx
PDS
70b’s
mass
to
5
dimensionalhydrodynamic
simulations
we
show
that
the
observedfeatures
can
be
well
explained
with
the
two
Jup
けてゆっくり増やした。軌道は固定
ﬁlteredand remaintrappedbeyond
the
gap
(Rice
et
al.
2006;
smallercavitysize(Pinilla
et
al.
2012;
Zhu
et
al.
2012).
The
other systems, like PDS 70, in mean motion resonance lends credwith
theof observed
deprojecteddistances
to 2018).
the cen200
estimates(Keppler
et
al.
2018;
Mülleretal.
W
planets
information,
providingstrongevidencethat
previously
proposed
theories
planet–diskinteractionareinibilitytothisformation
scenario
for
our
Solar
System.
Zhu
etal.
2012).
The
existenceof
CPDsaroundgiant
planetsisouter edge of the gap can actTheasobservations
a ﬁlter sosmall
particlescan- その後、惑星が重力的に円盤と相互作用するのを(Haffert
et al.
2019;
Keppler
et 70c:al.that2019).
With
theMse
with
MUSE
show
that
adaptive-opticsthreedifferent
masses
for
PDS
2.5,
5,
and
10
0 action, including resonant migration, particle trapping, size segregation, andﬁltration.
Our
simulations
suggestJu
also penetrateconceptuallyandnumerically
predicted(Quillen&theplanet-induced
gap,
whereaslarge
areassisted,
medium-resolution,
integral particles
field spectrographs
are highlyaxes
the orbital
periodratio
is2.3:1,
so theintwo
pla
許した。
two
planetsareinitially
placedat20
and35au,
anagre
the two 1998;
planetsLubow
are likely
in
2:1
mean
motionresonanceandcanremaindynamicallystableovermillion-year
efficient
instruments
toobserveaccretion
emission
spectrafrom–200 Trillingal. 1999;
Ayliffe2009;
Wardﬁltered and remainettrappedbeyondthe&gap(Rice
et al.
2006;−8Bate−7−1 planets could
planets
information.
Wesuspectthat
moreaccretinglocatedslightly
outsideof
2:1
mean
motionresonancewiththeobserved
deprojecteddistancestothe centr
–10
M
yr
,
rates
comparable
totheestimatesfromHαtimescales.
The
growthoftheplanets
at
10
Jup- その結果、0.1Myr
以内に2:1共鳴にハマった。
be foundcharacterizedin transition
diskswith thisas Thea consequenceofangularmomentum–400 & Canup
Zhu et2010),
al. 2012).
existence
ofand
CPDs
aroundgiant
planets
istechnique.
et toal.atthe2019;
Keppler
et al.only2019).
With out
the asem
In(Haffert
addition
simulations,
we carrysiobservations, does not destabilizeAnotherthe exciting
resonant
conﬁguration.
Largeduegrainsareﬁlteredthethree
gap
edge
and
opportunity,
which is now possible
to thealso conceptuallyandnumerically
predicted(Quillen&similartotheformationofcircumstellar
disks- common
gapは0.2Myrで準静的になった。
–600 conservationhighefficiency
of
both
the
HRSDI
data
processing
technique
and
axes
the
orbitalperiodratio
is2.3:1,
so
the
two
plan
small, (sub-)μm grains can ﬂow MUSE,
to theis thecircumplanetarydisks(CPDs)
and
the
inner
circumstellar
disk.
With
the
with
PDS70b
only.
detailed &investigationof accretionon short andTrilling
1998; Lubow et al. 1999; Ayliffe
Bate 2009;Wardaroundprotostars.
∆DEC (mas)PDS 70 c

1 June 2016

An Ideal Testbed for Planet–Disk Interaction: Two Giant Protoplanets in ResonanceShaping the PDS 70 Protoplanetary Disk
The Astrophysical Journal Letters, 884:L41 (12pp), 2019 October 20

t=0.6 Myr

1,13

2

3

4,5,6

Bae et al.

7

Jaehan Bae, Zhaohuan Zhu , Clément Baruteau , Myriam Benisty
89104
Stefano Facchini , Andrea Isella , Miriam Keppler, Laura M. Pérez, Cornelis P. Dullemond ,11,12, and Richard Teague
1
Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road NW, Washington, DC 20015, USA; jbae@carnegiescience.edu
PDS 70bしかないと、cavity
2
Department of Physics and Astronomy, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Las -Vegas, NV 89154, USA
3

IRAP, Université de Toulouse, CNRS, UPS, F-31400 Toulouse, Franceが離心率を持つ(e~0.1)
4
Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile
545auのところにサブミリ粒
Unidad Mixta Internacional Franco-Chilena de Astronomía (CNRS, UMI 3386), Departamento de Astronomía, Universidad de Chile,
CaminoEl Observatorio 1515,
Las Condes, Santiago, Chile
6
子リングができる→観測のUniv. Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France
7
Zentrum für Astronomie, Heidelberg University, Albert Ueberle Str. 2, D-69120 Heidelberg, Germany
74auと合わない
8
European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching, Germany
9
Department of Physics and Astronomy, Rice University, 6100 Main Street, MS-108, Houston, TX 77005, USA
10
Max Planck Institute for Astronomy, Königstuhl 17, D-69117, Heidelberg, Germany
11- PDS
70bとcが両方あると、cDepartment of Astronomy, University of Michigan, 311 West Hall, 1085 S. University Avenue, Ann Arbor,
MI 48109,
USA
12
Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USAの質量が2.5Mj と5Mjのとき、
Received 2019 August 20; revised 2019 September 18; accepted 2019 September 20; published 2019 October 15-

cavityが円になる。
Abstract- サブミリ粒子は63auにまで広While numerical simulations have been playing a key role in the studies of planet–diskがる。観測とまあまあ良い一interaction, testing
numerical results against observations has been limited so far. With the two directly 致。
imaged protoplanets
embedded in its circumstellar disk, PDS70 offers an ideal testbed for planet–disk interaction studies. Using twodimensional hydrodynamic simulations we show that the observed features can be well explained with the twoplanets in formation, providing strong evidence that previously proposed theories of planet–disk interaction are inaction, including resonant migration, particle trapping, size segregation, and ﬁltration. Our simulations suggest thatthe two planets are likely in 2:1 mean motion resonance and can remain dynamically stable over million-yeartimescales. The growth of the planets at 10−8–10−7MJupyr−1, rates comparable to the estimates from Hαobservations, does not destabilize the resonant conﬁguration. Large grains are ﬁltered at the gap edge and only
small, (sub-)μm grains can ﬂow to the circumplanetary disks (CPDs) and the inner circumstellar disk. With theAn Ideal Testbed for Planet–Disk Interaction: Two Giant Protoplanets in ResonanceShaping the PDS 70 Protoplanetary Disk
t=0.6 Myr
1

1,13

2

3

4,5,6

Jaehan Bae, Zhaohuan Zhu , Clément Baruteau , Myriam Benisty
89104
Stefano Facchini , Andrea Isella , Miriam Keppler, Laura M. Pérez

7, Cornelis P. Dullemond
11,12, and Richard Teague,

Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road NW, Washington, DC 20015, USA; jbae@carnegiescience.edu
2
Department of Physics and Astronomy, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154, USA- PDS 70cの質量が10Mj（重3IRAP, Université de Toulouse, CNRS, UPS, F-31400 Toulouse, France
4
Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las い）だと、リングが楕円になる
Condes, Santiago, Chile
5
Unidad Mixta Internacional Franco-Chilena de Astronomía (CNRS, UMI 3386), Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515,- 2.5Mjのときは、cの周りのガ
Las Condes, Santiago, Chile
6
Univ. Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France7
ス面密度のほうがbの周りより大Zentrum für Astronomie, Heidelberg University, Albert Ueberle Str. 2, D-69120 Heidelberg,
Germany
8European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching,
Germany
きい9Department of Physics and Astronomy, Rice University, 6100 Main Street, MS-108, Houston, TX 77005, USA
10
5Mjのときだと、PDS70b,cのMax Planck Institute for Astronomy, Königstuhl 17, D-69117, Heidelberg, -Germany
11
Department of Astronomy, University of Michigan, 311 West Hall, 1085 S. University Avenue, Ann Arbor, MI 48109, USA
12
周囲のガス面密度は同じくらい
Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA
02138, USA
Received 2019 August 20; revised 2019 September 18; accepted 2019 September 20; published2019 October 15- CO観測でみるとbの周囲の方がdepleteしているので、bよりcAbstractが軽いだろう。（bの質量は5Mj
While numerical simulations have been playing a key role in the studies of planet–disk interaction, testing
numerical results against observations has been limited so far. With the two に固定して考えている）
directly imaged protoplanets
embedded in its circumstellar disk, PDS70 offers an ideal testbed for planet–disk interaction studies. Using twodimensional hydrodynamic simulations we show that the observed features can be well explained with the twoplanets in formation, providing strong evidence that previously proposed theories of planet–disk interaction are in
Figure 1. (Left) The two-dimensional
gas surface density
distribution,migration,(middle) particle distribution,(right) azimuthally
averagedradial gas and dust
densityaction, including
resonant
particleandtrapping,size
segregation,
andﬁltration. Our simulations suggest that
distributions at t=0.6 Myr. From top to bottom, models without PDS70c, with M =2.5M , M =5M , and M =10M . Dashed circles in the left andtwoplanetsaveraged
are gaslikelyin 2:1Inmean
motionresonancecanmiddle panels show thethe
locationof the azimuthallypressure maximum.
the middle panels,
the red circles
show the sizeandof the Hill
radiusremainof the planets.dynamically stable over million-year
In the right panel, the red dashed line shows 1:2 outer Lindblad resonance location of PDS70c (PDS 70b in themodel without−8−7 PDS 70c), while−1the black dashed line
–10showMyr averaged, ratescomparable to the estimates from Hαgrowththe density
planets
at color
10histograms
shows the gas pressuretimescales.
maximum. The dottedThecurve shows
the initial ofgas surface
proﬁle. The
the Jupazimuthally
dust surface
density with sizes of (dark blue) 0.1–1μm, (green) 1–10μm, (red) 10–100μm, and (yellow) 0.1–1 mm, adopting 1au bin size in radius.
observations, does not destabilize the resonant conﬁguration. Large grains are ﬁltered at the gap edge and only
small, (sub-)μm grains can ﬂow3 to the circumplanetary disks (CPDs) and the inner circumstellar disk. With the
c

Jup

c

Jup

c

Jup

- 最初の0.1Myrで2:1共鳴に入る- 惑星の軌道は比較的安定（この後2Myrくらいまで）- cが2.5Mjのときは惑星は外に移動する。5Mj, 10Mjだと内側に移動する

cが重たいときの軌道移動

model locates closer to the center of the system compared withthe observation. With the submillimeter continuum ringAn Ideal Testbed for Planet–Disk Interaction: Two Giant Protoplanets in ResonanceShaping the PDS 70 Protoplanetary Disk
もっといい観測シ
7, Myriam
Mc Benisty= 2.5 Mj , Cornelis P. Dullemond , Bae et al.
10
4
11,12
ミュレーション
, Miriam Keppler, Laura M. Pérez , and Richard Teague

1,13Letters, 884:L41 (12pp),
2
3
The AstrophysicalJournal2019
October
20
Jaehan Bae, Zhaohuan Zhu ｂだけモデル。
, Clément Baruteau
観測されたダスト連続波
1

Stefano Facchini8, Andrea Isella

9

4,5,6

Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road NW, Washington, DC 20015, USA; jbae@carnegiescience.edu
2
Department of Physics and Astronomy, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154, USA
3
IRAP, Université de Toulouse, CNRS, UPS, F-31400 Toulouse, France
4
Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile
5
Unidad Mixta Internacional Franco-Chilena de Astronomía (CNRS, UMI 3386), Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515,
Las Condes, Santiago, Chile
6
Univ. Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble, France
7
Zentrum für Astronomie, Heidelberg University, Albert Ueberle Str. 2, D-69120 Heidelberg, Germany
8
European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching, Germany
9
Department of Physics and Astronomy, Rice University, 6100 Main Street, MS-108, Houston, TX 77005, USA
10
Max Planck Institute for Astronomy, Königstuhl 17, D-69117, Heidelberg, Germany
11
Department of Astronomy, University of Michigan, 311 West Hall, 1085 S. University Avenue, Ann Arbor, MI 48109, USA
12
Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
Received 2019 August 20; revised 2019 September 18; accepted 2019 September 20; published 2019 October 15

Abstract
While numerical simulations have been playing a key role in the studies of planet–disk interaction, testing
numerical results against observations has been limited so far. With the two directly imaged protoplanets
embedded in its circumstellar disk, PDS70 offers an ideal testbed for planet–disk interaction studies. Using twodimensional hydrodynamic simulations we show that the observed features can be well explained with the twoplanets in formation, providing strong evidence that previously proposed theories of planet–disk interaction are in
Figure 5. (a) The observed continuum emission at 855μm, reproduced from Isella et al. (2019). (b) A simulated continuum image with the PDS70b-only model,−1
action, including
resonant
migration,
sizebeam
segregation,and ﬁltration.
simulations
thatusing spatial resolution(93 × 74 mas
synthesizedbeam), particle
rms noisetrapping,level (18 μJy), disk inclination(51°. 7), Ourand position
angle suggest(156°. 7) comparable
to thetheSametwoasplanets
areleftlikely
motion Jup
resonance
dynamicallyoverobservation. (c)the middle
panel, inbut 2:1
with mean
the Mc=2.5Mmodel. Theand
CPDcandustremainmass is distributed
over astable
range ofdust million-yearsizes from 0.1μm to 1mm
−7
−1
−1
rms tonoise,
5 hr ofon-source(see the text). timescales.
(d) Same as the
middleright panel,but planets
using a 30×30
mas
synthesizedbeam
14μJybeam–10
MJupyr,andrates
comparable
therequiring
estimatesfromHα integration.
The
growthof theat 10−8
The synthesized
beam is shownin redthe bottom rightof eachpanel.
observations,does
notat destabilize
thecorner
resonant
conﬁguration.
Large grains are ﬁltered at the gap edge and only
small, (sub-)μm grains can ﬂow to the circumplanetary disks (CPDs) and the inner circumstellar disk. With the

RE P OR T
STAR FORMATION

Gas flow and accretion via spiral streamers andcircumstellar disks in a young binary protostar
F. O. Alves1*, P. Caselli1, J. M. Girart2,3 , D. Segura-Cox1, G. A. P. Franco4, A. Schmiedeke1, B. Zhao1
The majority of stars are part of gravitationally bound stellar systems, such as binaries. Observationsof protobinary systems constrain the conditions that lead to stellar multiplicity and subsequent
orbital evolution. We report high–angular resolution observations of the circumbinary disk around[BHB2007] 11, a young binary protostar system. The two protostars are embedded in circumstellar
disks that have radii of 2 to 3 astronomical units and probably contain a few Jupiter masses. Thesesystems are surrounded by a complex structure of filaments connecting to the larger circumbinary disk.
We also observe accretion and radio jets associated with the protobinary system. The accretion ispreferentially onto the lower-mass protostar, consistent with theoretical predictions.

We observed [BHB2007] 11 at 225.3 GHz(wavelength ~1.3 mm) with the Atacama Large
Millimeter/submillimeter Array (ALMA) (9).
The observations were centered on the circumbinary disk of [BHB2007] 11 and reveal its
internal structure. Figure 1 shows a multiscale
view of the dust distribution, extending fromthe B59 core scale (~20,600 AU) to the subdisk scale (~6 AU); the latter is the maximum
spatial resolution of our map, given the B59
distance of 163 pc (1 pc = 206,264.8 AU) (10).
The dust map reveals two compact sources that
we interpret as circumstellar disks around bothcomponents of a protobinary system, which
has a projected separation of ~28 AU. The
components were also seen in previous observations (11, 12) with the Karl G. Jansky Very
Large Array (VLA). We designate the individual components as [BHB2007] 11A (northernsource) and [BHB2007] 11B (southern source).
The dust emission seen in the ALMA dataarises from circumstellar disks with radii 3.1 ±0.6 AU ([BHB2007] 11A) and 2.1 ± 0.5 AU([BHB2007] 11B), similar to the radius of theasteroid belt in the Solar System. Their inclinations are ~40° between the disk normals andthe line of sight. From the continuum emission,
the masses of the circumstellar disks are esti-

Downloaded from http://science.sciencemag.org/ on October 6, 2019A

bout half of the stars in the solar neighborhood are in gravitationally boundstellar systems, such as binaries (1). The
mean separation between components,a few tens of astronomical units (AU;
1 AU = 149,597,870.7 km), is a consequence of
their formation process, thought to be fragmentation of the protostellar disk due to gravitational instabilities (2, 3). Observations ofyoung binary systems rarely probe such small
scales. We seek to investigate the dynamical
evolution of a binary system still embedded
in its natal cloud, where gas from a circumbinary disk is expected to accrete onto eachbinary component. In the protobinary accretion phase, theoretical models indicate thathigh–angular momentum material accretes
preferentially onto the less massive companion, which has a higher orbital angular momentum than the primary, causing ultimately
an equal share of mass among the individualcomponents (4–6).
[BHB2007] 11 (right ascension 17h11m23.18s,
declination −27°24′31.5″, J2000 equinox) isthe youngest member [age 0.1 to 0.2 million
years (7)] of the small cluster of young stellar
objects in the Barnard 59 (B59) core (part of
the Pipe Nebula molecular cloud), which isas the outcome of disk fragmentation (14).
The Toomre parameter, which quantifies the
dynamical state of the disk (15), shows thatthe [BHB2007] 11 circumbinary disk is stableagainst gravitational collapse (9), so the observed spirals are unlikely to be the result of
disk fragmentation. The total length of thefilaments is ~392 AU, their mean width is~12 AU, and the mean brightness temperature is 14 K, from which we estimate a mean
total mass of ~19 MJup (9). This corresponds toa mean mass per unit length of e10 M⊙ pc#1 ,which is below the critical value required to
produce fragmentation in the filaments. The
spiral shape centered on the protobinary system indicates dynamical interaction with theprotostars. Figure 1B shows that the geometrical center of the circumbinary disk is locatednear [BHB2007] 11A, within the angular resolution, suggesting that this source is theprimary, higher-mass object of the system. We
suggest that the filaments are inflow streamersfrom the extended circumbinary disk onto thecircumstellar disks of the protobinary system. We estimate a mass accretion rate fromthe circumbinary disk into the circumstellar
disk of e1:1 $ 10#5 M⊙ year#1 (9), which isconsistent with other protostellar sources (16).
The rotationally supported disk may be redistributing its angular momentum (through processes such as viscosity, magnetic braking, or
gravitational torques), causing material to fall
into the gravitational potential wells of theindividual protostars. Although other factors
such as envelope accretion into the circumbinary disk, misaligned disks, or eccentric binary orbit could also produce substructuresuch as filaments in the circumbinary disk
(6, 17, 18), accretion streamers feeding thecircumstellar disks can still occur in thosescenarios (6, 17).
We measured kinematics by reanalyzing (9)previous observations (8) of the CO (angularmomentum quantum number J = 2→1) molecular emission line in [BHB2007] 11. The
relative positions of the molecular gas in eachvelocity channel of the emission spectra were
determined with positional accuracies better than 0.05″ (9). The systemic velocity ofFig. 2. Small-scale kinematics in [BHB2007] 11
measured from CO
molecular line emission.
(A) High-velocity components of the CO emission(with respect to the ambient local standard of rest
velocity of [BHB2007] 11,
vlsr ~ 3.6 km s−1) overlaid
on the continuum map(gray scale). Circles indicate the position of CO
emission peaks in eachvelocity channel (see thecolor bar). CO data
between −2 and 9 km s−1(indicated as a shaded
area in the color bar) arenot shown because mostgas close to the ambient velocity is filtered out by the interferometer and/or
arises from extended emission from outflows or the envelope. Circle sizes denotethe uncertainty on the absolute position (9). (B) CO mean spectrum extracted
from the disk area showing the CO velocity channels used in (A). The shaded

areas indicate the CO velocity components that exceed the reference
H2CO spectrum associated with the rotation of the circumbinary disk (9). The
faint dashed lines show the strong filtering of the CO line near the systemic
velocity of the source.

Systematic Variations of CO Gas Abundance with Radius in Gas-rich Protoplanetary
Disks
Ke Zhang1 , Edwin A. Bergin1 , Kamber R. Schwarz2 , Sebastiaan Krijt3 , Fred Ciesla4
1

Department of Astronomy, University of Michigan, 323 West Hall, 1085 S. University Ave, Ann Arbor, MI 48109,
USA; 2 Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd, Tucson, AZ 85721, USA; 3
Department of Astronomy/Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ
85721, USA; 4 Department of the Geophysical Sciences, The University of Chicago, 5734 South Ellis Avenue, Chicago,
IL 60637, USA E-mail contact: kezhang at umich.edu
CO is the most widely used gas tracer of protoplanetary disks. Its abundance is usually assumed to be an interstellar
ratio throughout the warm molecular layer of the disk. But recent observations of low CO gas abundance in many
protoplanetary disks challenge our understanding of physical and chemical evolutions in disks. Here we investigate
the CO abundance structures in four well-studied disks and compare their structures with predictions of chemical
processing of CO and transport of CO ice-coated dust grains in disks. We use spatially resolved CO isotopologue line
observations and detailed thermo-chemical models to derive CO abundance structures. We find that the CO abundance
varies with radius by an order of magnitude in these disks. We show that although chemical processes can eﬃciently
reduce the total column of CO gas within 1 Myr under an ISM level of cosmic-ray ionization rate, the depletion mostly
occurs at the deep region of a disk. Without suﬃcient vertical mixing, the surface layer is not depleted enough to
reproduce weak CO emissions observed. The radial profiles of CO depletion in three disks are qualitatively consistent
with predictions of pebble formation, settling, and drifting in disks. But the dust evolution alone cannot fully explain
the high depletion observed in some disks. These results suggest that dust evolution may play a significant role intransporting volatile materials and a coupled chemical-dynamical study is necessary to understand what raw materials
are available for planet formation at diﬀerent distances from the central star.
Accepted by ApJ
http://arxiv.org/pdf/1908.03267

An Episodic Wide-angle Outflow in HH 46/47
Yichen Zhang1 , Héctor G. Arce2 , Diego Mardones3,4 , Sylvie Cabrit5,6 , Michael M. Dunham7 , Guido
Garay3 , Alberto Noriega-Crespo8 , Stella S. R. Oﬀner9 , Alejandro C. Raga10 , and Stuartt A. Corder11Systematic Variations of CO Gas Abundance with Radius in Gas-rich Protoplanetary
Disks Radial variation of CO gas abundance3
Ke Zhang1 , Edwin A. Bergin1 , Kamber R. Schwarz2 , Sebastiaan Krijt3 , Fred Ciesla4
1

Department of Astronomy, University of Michigan, 323 West Hall, 1085 S. University Ave, Ann Arbor, MI 48109,
3
USA; 2 Lunar and Planetary Laboratory, University of -Arizona,
1629
E.
University
Blvd,
Tucson,AZ
85721,
USA;
背景
Department of Astronomy/Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ
原始惑星系円盤の輝線観測でよく使うのがCO
485721, USA; Department of the Geophysical Sciences, The University of Chicago, 5734 South Ellis Avenue, Chicago,
IL 60637, USA E-mail contact: kezhang at umich.edu - だが、ISMよりもCO abundance が低いことがわかっている
CO is the most widely used gas tracer of protoplanetary disks.
Its abundance is usually assumed to be an interstellar

ratio throughout the warm molecular layer of the disk. But
recent observations of low CO gas abundance
many
CH3OH,inCH4な- COは他の状態に遷移したか？CO2,
protoplanetary disks challenge our understanding of physicalど。
and chemical evolutions in disks. Here we investigate
the CO abundance structures in four well-studied disks and compare their structures with predictions of chemical- あるいは、ダストに凍りついたか？
processing of CO and transport of CO ice-coated dust grains
in disks. We use spatially resolved CO isotopologue line
depletionのradial
を4天体につobservations and detailed thermo-chemical models to derive
CO abundance
structures. We findvariationthat the COabundance- 今回は、COvaries with radius by an order of magnitude in these disks.いて調べ、それを説明するにはどんなモデルが必要かを
We show that although chemical processes can eﬃciently
reduce the total column of CO gas within 1 Myr under an ISM level of cosmic-ray ionization rate, the depletion mostly
議論する
occurs at the deep region of a disk. Without suﬃcient vertical mixing, the surface layer is not depleted enough to
reproduce weak CO emissions observed. The radial profiles of CO depletion in three disks are qualitatively consistent
with predictions of pebble formation, settling, and drifting in disks. But the dust evolution alone cannot fully explain
the high depletion observed in some disks. These results suggest that dust evolution may play a significant role intransporting volatile materials and a coupled chemical-dynamical study is necessary to understand what raw materials
are available for planet formation at diﬀerent distances from the central star.
Accepted by ApJ
http://arxiv.org/pdf/1908.03267

An Episodic Wide-angle Outflow in HH 46/47

Radial variation of CO gas abundance

7

ionization
the disk Protoplanetaryis simulated with an attenuaSystematic Variations of CO Gas Abundance with Radius
ininside
Gas-rich2
tion
lengthof96
gcm(Umebayashi & Nakano 1981;
Disks
6

Bergin et3 al. 2007). For 4the given radiation field, theまず、スムーズな円盤モデルでデータをフィットしてガKe Zhang , Edwin A. Bergin , Kamber R. Schwarz , Sebastiaan
KrijtFred Ciesla solves the chemical evolution
code
then, simultaneously
Zhang et al.

1

1

2

Table 4. Disk Model Parameters

ス・ダスト構造を求める
andS.gas
thermal structurein thedisk.MI
The48109,
chemical netDepartment
of TW
Astronomy,of Michigan,
323 West Hall, 1085
University
Ave, Ann
Arbor,DM TauHya HD 163296 University
IM Lup Units
Definition3
has 467Blvd,
speciesand 4801
includingthe
0.8
1
surfacedensity index of gas
その中で化学進化計算（RAC2D,Du andBerginUSA; 2 Lunar1 and0.75
Planetary
Laboratory,
Universityof Arizona, -1629
E.workUniversity
Tucson,AZ reactions,
85721,
USA;
1
1
0.1
0.3
surface density index of large grain
full gas-phasenetwork
fromthe UMIST
database,
disDepartmentofAstronomy/Steward
Observatory,
The
UniversityofArizona,933
North
CherryAvenue,Tucson,
AZ
R
270
104
165
100
(AU) characteristic radius of gas
2014）を動かして、最終的にCOの輝度を計算する。
sociation of H2 O and OH by Ly↵ photons, adsorption
4
R
135
60
90
100
(AU) characteristic radius of large grain
85721, USA; Department of the Geophysical Sciences, The University of Chicago, 5734 South Ellis Avenue, Chicago,M
4.00E-04 4.00E-04
1.20E-03
1.70E-03 (M ) mass of large grain
and desorption of species on the dust grain surface either
IL 60637,
USAkezhang
atofumich.edu
M
1.00E-04E-mail1.00E-04 contact:
3.00E-04
1.70E-05(M ) mass
small grain
thermally or induced by cosmic rays and UV photons,
1

g

mm

g
c
mm
c

mm

small

0.2

mm

0.2

0.2

0.2

scale fraction of large grain

and two-bodyreactions
onto
thebedust
grain surface.
CO isH thewidelyused
gas 8tracer
disks. Its abundanceis usuallyassumedan interstellar(AU) most
66
8.5(AU) ofgas protoplanetaryscale height at 100AU
1.25
1.25
1.08
1.2
flaring parameter
The chemical
modelsareabundance
initialized inwitha composiratioR throughoutthewarm
molecular
layer
of
the
disk.
But
recentobservations
of
low
CO
gas
many
19
1
0.5
0.2
(AU) inner radius of large graintion evolutions
listed in theof Duwe& investigate
Bergin (2014). In
R
3
4
0.5
0.2
inner radius of gas/small
protoplanetarydisks
challenge
our (AU)
understandingof grainphysical and chemicalin Tabledisks.1 Hereparticular, all carbon is initially in CO gas with an abunR
300
70
600
313
(AU) outer radius of large grain
the CO
abundance
structuresin fourwell-studied disks and compare their structures withpredictions of chemical
4
R
500
200
600
1200
(AU) outer radius of gas/small grain
dance of 1.4⇥10 relative to H atoms and a binding enprocessing of CO and transport of CO ice-coated dust grains in disks. Weusespatially
resolvedCOisotopologue
line
ergy of 855 K for CO ice (Öberg et al. 2005). We let theobservations and detailed thermo-chemical models to derive CO abundance
structures.
themodels.
CO abundancechemistry
run Wefor 1findMyrthatfor all
No isotopologue
varies with radius by an order of magnitude in these disks. We show that
although chemical
processes
eﬃciently
fractionationis consideredin thecanchemical
network, as
ALMA observations of
reduce theSEDtotal column of CO gas C18O/13COwithinlines1 Myr under an ISM level of cosmic-ray
ionization
rate, theto
depletion
mostly in masthe fractionation
is expected
be insignificant
Disk gas chemistry,
startingwith constantoccurs at theregionof a disk. Without suﬃcient vertical mixing,sivethe diskssurfaceis not depleted
toreﬁne deep
scale
likelayer
this sample(Miotelloenoughet al. 2014).
We
CO abundance acrossheight h(R)the disk
rescalethe output
CO qualitatively
abundance byconsistent
the local ISM rareproduce
weak CO emissions
observed.
TheradialprofilesofCO
depletion
in
three
disks
are
Disk Structure
,T ,
13
18
Line ray-tracing
Figure3.
The best-fitting
SED modelsof the,Tradial variationof four disks.
CO abundance
tios
of
CO/
CO=
69,
and
CO/C
O=570
to generatewith predictions of pebble
formation,
settling,
andCOdrifting
in disks. But the dust evolution alone cannot fully
explain
C O/ COline cube
gas
structurefordifferent CO
are
black
dots and the best-fittings
RADMC3D The photometry data models
CO isotopologue
abundances(Wilson 1999).
depletionlevelsthe high depletion observedinsome
disks.
These
resultssuggestthat
dust
evolution
may
play
a
significant
role
in
RAC2D
I_modelmodels are overlaid as solid
grey lines.
Using
the
gas
temperature
andCO
abundance
strucRAC2D
transporting volatile materials and a coupled chemical-dynamical study is necessary to understand what raw materials
tures, we compute line images using the ray-tracing
are available for planet
formation at diﬀerent distances from the central star.
cosmic-ray,
100

mm
in
g
in
mm
out
g
out

gas

dust

gas

dust

gas, small grainfrom scattered lightimages,large grain from(sub)mm continuum

Accepted by ApJ

18Fx, Fuv,

13

3.2.2. Stellar parameters

We adopt the e↵ective temperatures and luminosihttp://arxiv.org/pdf/1908.03267
Figure 2. An ties
outline ofof thethemodeling
processes.stars
The output
of each thestep is literature
highlighted in red.and rescalecentralfromlar velocity. For the thelarge stellar
grain population,we• using
HD 163296:
we employthe 2basic
strucluminosities
thelatestGaia
measuremm
use mm =1, Rc =135 AU, and an inner radiusture of Isella et al. (2016) which fitted thements.
The inclination
andanglesareadoptedof 20 AU
based on themodelof Andrews
et al.
1.3 mm position
continuum
emissionand thegeneralsizes
AnEpisodic
Wide-angle
Outflow
in
HH
46/47
13
18
(2011), which matches the 880µm continuum ob-of CO/ CO/C O (2-1) isotopologue emissions.

module of RAC2D, assuming an LTE condition. We initially simulate the images at a 2 AU spatial resolution
and 10⇥spectral resolution as the observations, and thenconvolve model images to the same spatial and spectral
resolution as observations.
3.4. Parameter Testsbetween gas and dust (Du & Bergin 2014). The clear deviation from 20 K is seen in the outer disk region (>300 au) of IM Lup
wheredensities
low. The third column:
densityin
profilesof CO gas Protoplanetary
and CO ice.
Systematic Variations
oftheCOGasareAbundance
withcolumn
RadiusGas-rich

Disks

In Figure 4, we show the CO gas abundance and gas
163296 model, its CO mid-plane snowline is between
8Zhang
et al.
temperature
structuresinthe standard
models (⇣CRKrijt= 3 , Fred
50-70 AU,
consistent
with the previous estimation from1
1
2
4
Ke Zhang , Edwin A. Bergin , Kamber
R.
Schwarz,
Sebastiaan
Ciesla1.36 ⇥ 10 18 s 1 ) of these four disks. All four disks
C18 O and N2 H+ line observations, after correcting to1
Department of Astronomy,
Universityof Michigan,
323theWest1085 S. University
Ave, distance
Ann Arbor,show
a molecularlayer in which
CO Hall,gas abundance
the Gaia2(Qi etMI
al.48109,
2015). For the IM Lup
is closeto 10 4 .University
This layered
structure 1629
has beenseen
model,
its CO ice
to appear
USA; 2 Lunar and Planetary
Laboratory,of Arizona,
E. University
Blvd, Tucson,
AZstarts
85721,
USA; 3around 30 AU, but
in channelObservatory,
maps of CO line
163296 933 North
its COCherry
ice column
densityincreases
Department of Astronomy/Steward
Theobservations
University ofofHD
Arizona,Avenue,Tucson,AZ slowly with radius
and
IM
Lup
(Rosenfeld
etal.
2013b;Pinteetal.
2018a).
comparedwith
otherdisks,
because
the
IM
Lup
disk
4
85721, USA; Department of the Geophysical Sciences, The University of Chicago, 5734 South Ellis Avenue, Chicago,
The last column in Figure 4 shows the column density
is highly flaring and has a thicker CO gas layer than
結果（普通の宇宙線強度を仮定した場合）
IL 60637, USA E-mail contact:kezhang at umich.edu
distributions CO gas and ice in the four disk models.
others.
(gas+ice)column density
distribution
is close is usually
In short,
the fourstandard
models (⇣CR = 1.36⇥10 18
CO is the most widely usedThegas CO
tracerof protoplanetarydisks.
Its abundanceassumedto be
an interstellar
4
1
to
10
at
all
radii,
indicating
very
little
CO
has
been
s
) all
layered CO ingasmany
structure and the midratio throughout the warm molecular layer of the disk. But recent observations of low
COshow
gas aabundance
convertedtoothercarboncarriers
after
1
Myr
in
these
plane
CO
snowlinelocationsareconsistent
withexisting
protoplanetary disks challenge our understanding of physical and chemical evolutions in disks. Here we investigate
low CR rate models.
observational constraints. In these models, less thanthe CO abundance structuresWhen
in fourwell-studied disks and compare their structureswith predictions of chemical
no significant conversion of CO into other car10% of total CO (gas+ice) have been converted to otherprocessing of CO and transportof CO ice-coateddust grains
We use spatiallyresolvedisotopologue
lineriers occurs,
the CO snowline
locationinisdisks.
predominantly
carboncarriersCO
after
1 Myr.
observations and detailed thermo-chemical
modelsto derive
COofabundance
structures. We find that the CO abundance
determined by thethermalstructure
the disk. DM
varies with radius by an orderin thesedisks.
Weandshow
althoughCOが別の化学種になったのは10%以下であっchemicaleﬃciently
Tauofis magnitude
the coldest disk
in oursampleits that
CO mid4.2. CO processes
abundance canstructuresin models with a highplanearound10-15
AU levelin thecosmic-ray
rate
reduce the total column of CO
gassnowline
within 1isMyr
underan ISMof standard
cosmic-ray ionization rate, the depletion
mostlyた。
model.
In
the
TW
Hya
model,
theCO
mid-plane
snowoccurs at the deep region of a disk. Without suﬃcient vertical mixing, the surface layer
depletedenoughofto
Figureis5 notshows
the comparison
CO gas column denline is around 20 AU, consistent with 21±1.3 AU derived
distribution
in high andstandard models (⇣CR =reproduce weak CO emissions
observed.
The radial profiles of CO depletion in threesitydisks
are qualitatively
consistent
13 18
from C O (3-2) line observations (Zhang et al. 2017)
17
1
18
1
1.36
⇥
10
s
vs.
1.36
⇥
10
s
). Models of DM
with predictions of pebble formation,
settling,
anddrifting
indisks.
Butthedust
evolutionalone
cannotfully
explain+and the N2 H line image (Qi et al. 2013). For the HD
Tau may
and TWshow substantial
the high depletion observed in some disks. These results suggest that dust evolution
playHyaa significant
role in CO gas depletions--transporting volatile materials and a coupled chemical-dynamical study is necessary to understand what raw materials
are available for planet formation at diﬀerent distances from the central star.
Acceptedby
ApJ
Figure 4. Chemical structures of the standard models (⇣s 1 ). First column: CO gas abundance; second
column:gas temperature. The 20K contours are plotted to guide eyes for a general expectation of CO freeze-out location, but
http://arxiv.org/pdf/1908.03267
the actually freeze-out level depends on the local number densities of CO gas and ice as well as the temperature di↵erences
between gas and dust (Du & Bergin 2014). The clear deviation from 20 K is seen in the outer disk region (>300 au) of IM Lup
where the densities are low. The third column: column density profiles of CO gas and CO ice.
CR =1.36⇥10

18

An Episodic Wide-angle Outflow in HH 46/47

Systematic Variations of CO Gas Abundance with Radius in Gas-rich Protoplanetary
10
Zhang et al.
Disks
Ke Zhang1 , Edwin A. Bergin1 , Kamber R. Schwarz2 , Sebastiaan Krijt3 , Fred Ciesla4
宇宙線強度を1桁あげてみた1
Department of Astronomy, University of Michigan, 323 West Hall, 1085 S. University Ave, Ann Arbor, MI 48109,
USA; 2 Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd, Tucson, AZ 85721, USA; 3
Department of Astronomy/Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ
85721, USA; 4 Department of the Geophysical Sciences, The University of Chicago, 5734 South Ellis Avenue, Chicago,
IL 60637, USA E-mail contact: kezhang at umich.edu
CO is the most widely used gas tracer of protoplanetary disks. Its abundance is usually assumed to be an interstellar
ratio throughout the warm molecular layer of the disk. But recent observations of low CO gas abundance in many
protoplanetary disks challenge our understanding of physical and chemical evolutions in disks. Here we investigate
the CO abundance structures in four well-studied disks and compare their structures with predictions of chemical
processing of CO and transport of CO ice-coated dust grains in disks. We use spatially resolved CO isotopologue line
observations and detailed thermo-chemical models to derive CO abundance structures. We find that the CO abundance
varies with radius by an order of magnitude in these disks. We show that although chemical processes can eﬃciently
reduce the total column of CO gas within 1 Myr under an ISM level of cosmic-ray ionization rate, the depletion mostly
occurs at the deep region of a disk. Without suﬃcient vertical mixing, the surface layer is not depleted enough to
reproduce weak CO emissions observed. The radial profiles of CO depletion in three disks are qualitatively consistent
with predictions of pebble formation, settling, and drifting in disks. But the dust evolution alone cannot fully explain
the high depletion observed in some disks. These results suggest that dust evolution may play a significant role intransporting volatile materials and a coupled chemical-dynamical study is necessary to understand17
1 what raw materials
Figure 5. Comparison between high cosmic-ray ionization models and standard models (⇣CR = 1.36⇥10
s vs. 1.36⇥10 18
are
1 available for planet formation at diﬀerent distances from the central star.
s ). Top: CO gas column density in high ⇣(blue dash line) and standard models (black solid line). Bottom: C18 O line
CR

surfacebrightness
profiles in the models with di↵erent ⇣CR rates (blue dash and black solids lines). The observed profiles are in
Acceptedby ApJgrey.

http://arxiv.org/pdf/1908.03267

An Episodic Wide-angle Outflow in HH 46/47

modelsfromthe Theof observed
standard profilesgeneralsurface brightness profiles in the models with di↵erent ⇣CR(Irates(blueindash
and deviating
black solids
lines).
are in trends of carbon elemental abundance suggested
CO ) varyby other carbon carriers. Bergner et al. (2019) anamodels by ± 0.2. These results show that ⌃CO repgrey.
Systematic Variations of CO Gas
AbundancewithintheGas-richlyzed C2Protoplanetary
H radial brightness distributions in the same
resents
well the gas column
densityRadiuschange within
three disks and their models required a high depletion
mid-plane CO snowline, but it becomes less sensitive toDisksof elemental carbon abundance (by a factor of 10-100)
the gas surface density changes beyond the CO snowline
2
3
4
Ke Zhang1 , Edwin A. Bergin1 , Kamber, accounts
Sebastiaan
Krijt, FredCieslabetween 100-200 AU and only a modestly depletion beas theR.
COSchwarz
gas layer only
for a small
fractionofyond 200 AU (by a factor of 1-10). Therefore, the CO
the total gas column. The ICO profiles only change less1
Department of Astronomy, University ofthan
Michigan,
323 Westof Hall,1085index.
S. University Ave,
Annprofiles
Arbor,
MI
48109,a general depletion of
depletion
likelyrepresent
30% for uncertainty
0.2 in theelemental
abundancein the3 atmospheres of these
USA; 2 Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd, carbon
Tucson,AZ 85721,
USA;
4.4. Radial distribution of CO gas abundance:disks.
Department of Astronomy/Steward Observatory, The models
UniversityofArizona,933
North
CherryAvenue,Tucson,AZ
vs. observations
Summary of model results: 1. In detailed thermo4
85721, USA; Department of the GeophysicalSciences,Theof Chicago,5734 South
Ellis
Avenue,chemicalmodelsfor the Chicago,
four disks, aRadial
high CRvariation
ionization ofHere
we compare
the University
surface brightness
distributions
rate can significantly reduce the CO gas column between
IL 60637, USA E-mail contact: kezhang atofumich.edu
CO lines (ICO ) between observations and our stan50-100 AU up to a factor of 20 after 1 Myr. However,
CO is the most widely used gas tracer of protoplanetary disks. Its abundance is usually assumed
to bebyanchemicalinterstellar
the depletions
processing mostly happen
at theinterior of thesemodel disks, and the reratio throughout the warm molecular layer of the disk. But recent observations of low CO
gasdeep
abundance
in manyabundance structures cannot reproduce theprotoplanetary disks challenge our understanding of physical and chemical evolutions in sulting
disks.COHere
we investigate
weak CO isotopologue lines observed. 2. Comparing
the CO abundance structures in four well-studied disks and compare their structures withof modelschemicalthesepredictions
thermo-chemical
to spatially resolved observations,find that the CO
processing of CO and transport of CO ice-coated dust grains in disks. We use spatially resolved
COweisotopologue
linegas abundance likely
variesthat
significantly
radius. An interesting patternobservations and detailed thermo-chemical models to derive CO abundance structures. We findthe COwith
abundancein the radial profiles is that the CO gas abundance isvaries with radius by an order of magnitude in these disks. We show that although chemical
processes
candiskeﬃciently
low inintermediate
region outside the mid-plane
COrate,snowlines,
but gradually
increases with radius to a
reduce the total column of CO gas within 1 Myr under an ISM level of cosmic-ray ionization
the depletion
mostlyvalue
in the outermost
occurs at the deep region of a disk. Without suﬃcient vertical mixing, the surface layerhigher
is notdepletedenoughregion.
to
5. consistentDISCUSSION
reproduce weak CO emissions observed. The radial profiles of CO depletion in three disks are qualitatively
とにかく、観測されたほどの
5.1. COdepletionmechanisms
with predictions of pebble formation, settling, and drifting in disks. But the dust evolution alone cannot
fully
explainof nearbystarinformation regions sugthe high depletion observed in some disks. These results suggest that dust evolution mayCurrent
play depletionが再現できない。
asurveyssignificantrolegest that verticalgas mass derived
from CO observations is 1-2transporting volatile materials and a coupled chemical-dynamical study is necessary to understandwhat rawmixingが必要か？
materials
orders of magnitude too low compared to the canonic
are available for planet formation at diﬀerent distances from the central star.
CO ratio in ISM (Ansdell et al. 2016; Long et al. 2017;

Figure6. Top row:
The total gas surface density profiles for models with di↵erent . Middle row: the CO gas columnMiotellodensity et al. 2017). In a broad sense, two types ofAcceptedby ApJ
depletion
profiles after 1 Myr chemical evolution and a ⇣CR of 1.36⇥10 18 s 1 . Bottom row: model C18 O line brightness distributions
vs. mechanisms have been proposed: (1) the firstone is chemical processes that convert CO into other less
http://arxiv.org/pdf/1908.03267
observations(grey line).
volatile molecules (e.g., CO2 , CH3 OH, CH4 ) (Aikawa
et al. 1999; Bergin et al. 2014; Reboussin et al. 2015;
Eistrup et al. 2016; Yu et al. 2016; Schwarz et al. 2018;
An Episodic Wide-angle Outflow in HH 46/47

http://arxiv.org/pdf/1908.00897

Kinematic signatures of cluster formation from cool collapse in the Lagoon Nebulacluster NGC 6530
Nicholas J. Wright1 and Richard J. Parker2
1

Astrophysics Group, Keele University, Keele, ST5 5BG, UK; 2 Department of Physics & Astronomy, The Universityof Sheﬃeld, Hicks Building, Sheﬃeld, S3 7RH, UK
E-mail contact: n.j.wright at keele.ac.uk
We examine the mass-dependence of the velocity dispersion of stars in the young cluster NGC 6530 to better understandhow it formed. Using a large sample of members we find that the proper motion velocity dispersion increases withstellar mass. While this trend is the opposite to that predicted if the cluster were developing energy equipartition, it
is in agreement with recent N-body simulations that find such a trend develops because of the Spitzer instability. In
these simulations the massive stars sink to the centre of the cluster and form a self-gravitating system with a higher
velocity dispersion. If the cluster has formed by the cool collapse of an initially substructured distribution then thisoccurs within 1-2 Myr, in agreement with our observations of NGC 6530. We therefore conclude that NGC 6530
formed from much more extended initial conditions and has since collapsed to form the cluster we see now. This
cluster formation model is inconsistent with the idea that all stars form in dense, compact clusters and provides thefirst dynamical evidence that star clusters can form by hierarchical mergers between subclusters.
38
Accepted by MNRAS
https://arxiv.org/pdf/1908.11398

There is no magnetic braking catastrophe: Low-mass star cluster and protostellar discformation with non-ideal magnetohydrodynamics
James Wurster1 , Matthew R. Bate1 and Daniel J. Price2
1

School of Physics and Astronomy, University of Exeter, Stocker Rd, Exeter EX4 4QL, UK; 2 School of Physics andAstronomy, Monash University, VIC 3800, Australia
E-mail contact: j.wurster at exeter.ac.uk
We present results from the first radiation non-ideal magnetohydrodynamics (MHD) simulations of low-mass starcluster formation that resolve the fragmentation process down to the opacity limit. We model 50 M⊙ turbulent clouds

Accepted by MNRAS
https://arxiv.org/pdf/1908.11398

There is no magnetic braking catastrophe: Low-mass star cluster and protostellar discformation with non-ideal magnetohydrodynamics
James Wurster1 , Matthew R. Bate1 and Daniel J. Price2
1

School of Physics and Astronomy, University of Exeter, Stocker Rd, Exeter EX4 4QL, UK; 2 School of Physics andAstronomy, Monash University, VIC 3800, Australia
E-mail contact: j.wurster at exeter.ac.uk
We present results from the first radiation non-ideal magnetohydrodynamics (MHD) simulations of low-mass starcluster formation that resolve the fragmentation process down to the opacity limit. We model 50 M⊙ turbulent clouds
initially threaded by a uniform magnetic field with strengths of 3, 5 10 and 20 times the critical mass-to-magnetic flux
ratio, and at each strength, we model both an ideal and non-ideal (including Ohmic resistivity, ambipolar diﬀusion andthe Hall eﬀect) MHD cloud. Turbulence and magnetic fields shape the large-scale structure of the cloud, and similar
11−3<
structures form regardless of whether ideal or non-ideal MHD is employed. At high densities (106 <n
10cm), all∼ H∼models have a similar magnetic field strength versus density relation, suggesting that the field strength in dense coresis independent of the large-scale environment. Albeit with limited statistics, we find no evidence for the dependence of
the initial mass function on the initial magnetic field strength, however, the star formation rate decreases for models
with increasing initial field strengths; the exception is the strongest field case where collapse occurs primarily along
field lines. Protostellar discs with radii >∼20 au form in all models, suggesting that disc formation is dependent on thegas turbulence rather than on magnetic field strength. We find no evidence for the magnetic braking catastrophe, andfind that magnetic fields do not hinder the formation of protostellar discs.
Accepted by MNRAS
https://arxiv.org/pdf/1908.03241

Properties of Density and Velocity Gaps Induced by a Planet in a Protoplanetary Disk
Han Gyeol Yun1 , Woong-Tae Kim1,2 , Jaehan Bae3 , and Cheongho Han4
1

Department of Physics & Astronomy, Seoul National University, Seoul 08826, Korea; 2 Center for Theoretical Physics

https://arxiv.org/pdf/1908.03241

Properties of Density and Velocity Gaps Induced by a Planet in a Protoplanetary Disk
Han Gyeol Yun1 , Woong-Tae Kim1,2 , Jaehan Bae3 , and Cheongho Han4
1

Department of Physics & Astronomy, Seoul National University, Seoul 08826, Korea; 2 Center for Theoretical Physics(CTP), Seoul National University, Seoul 08826, Korea; 3 Department of Terrestrial Magnetism, Carnegie Institution
for Science, 5241 Broad Branch Road NW, Washington, DC 20015, USA; 4 Department of Physics, Chungbuk National
University, Cheongju 28644, Korea
E-mail contact: hangyeol at snu.ac.kr
Gravitational interactions between a protoplanetary disk and its embedded planet is one of the formation mechanismsof gaps and rings found in recent ALMA observations. To quantify the gap properties measured in not only surface
density but also rotational velocity profiles, we run two-dimensional hydrodynamic simulations of protoplanetary disks
by varying three parameters: the mass ratio q of a planet to a central star, the ratio of the disk scale height hp tothe orbital radius rp of the planet, and the viscosity parameter α. We find the gap depth δΣ in the gas surface
density depends on a single dimensionless parameter K ≡ q 2 (hp /rp )−5 α−1 as δΣ = (1+0.046K)−1, consistent
with the previous results of Kanagawa et al. (2015a). The gap depth ?V in the rotational velocity is given by
δV = 0.007(hp /rp )K 1.38 /(1 + 0.06K 1.03). The gap width, in both surface density and rotational velocity, has aminimum of about 4.7hp when the planet mass Mp is around the disk thermal mass Mth , while it increases in a
power-law fashion as Mp /Mth increases or decrease from unity. Such a minimum in the gap width arises because
spirals from sub-thermal planets have to propagate before they shock the disk gas and open a gap. We compare ourrelations for the gap depth and width with the previous results, and discuss their applicability to observations.
Accepted by ApJ
http://arxiv.org/pdf/1908.11065

39http://arxiv.org/pdf/1908.03267

An Episodic Wide-angle Outflow in HH 46/47
Yichen Zhang1 , Héctor G. Arce2 , Diego Mardones3,4 , Sylvie Cabrit5,6 , Michael M. Dunham7 , Guido
Garay3 , Alberto Noriega-Crespo8 , Stella S. R. Oﬀner9 , Alejandro C. Raga10 , and Stuartt A. Corder111Star and Planet Formation Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan;
2
Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520, USA; 3 Departamento de Astronomı́a, Universidad de Chile, Casilla 36-D, Santiago, Chile; 4 Centre for Astrochemical Studies, Max-PlanckInstitute for Extraterrestrial Physics, Giessenbachstrasse 1, 85748, Garching, Germany; 5 LERMA, Observatoire deParis, UMR 8112 du CNRS, ENS, UPMC, UCP, 61 Av. de l’Observatoire, F-75014 Paris, France; 6 Institut dePlanétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, 38041, France; 7 Department of Physics,
State University of New York at Fredonia, 280 Central Avenue, Fredonia, NY 14063, USA; 8 Space Telescope Science
Institute, 3700 San Martin Dr., Baltimore, MD 21218, USA; 9 Department of Astronomy, The University of Texas atAustin, Austin, TX 78712, USA; 10 Instituto de Ciencias Nucleares, UNAM, Ap. 70-543, 04510 D.F., Mexico; 11 Joint
ALMA Observatory, Av. Alonso de Córdova 3107, Vitacura, Santiago, Chile E-mail contact: yichen.zhang at riken.jp
During star formation, the accretion disk drives fast MHD winds which usually contain two components, a collimatedjet and a radially distributed wide-angle wind. These winds entrain the surrounding ambient gas producing molecular
outflows. We report recent observation of 12 CO (2–1) emission of the HH 46/47 molecular outflow by the Atacama
Large Millimeter/sub-millimeter Array, in which we identify multiple wide-angle outflowing shell structures in boththe blue and red-shifted outflow lobes. These shells are highly coherent in position-position-velocity space, extending
−1
4
to >
40–50
km
s
in
velocityand10
au in space with well defined morphology and kinematics. We suggest these∼outflowing shells are the result of the entrainment of ambient gas by a series of outbursts from an intermittent wideangle wind. Episodic outbursts in collimated jets are commonly observed, yet detection of a similar behavior inwide-angle winds has been elusive. Here we show clear evidence that the wide-angle component of the HH 46/47
protostellar outflows experiences similar variability seen in the collimated component.
Accepted by ApJ
http://arxiv.org/pdf/1908.00689

40

Disk Kinematics and Stability in High-Mass Star Formation: Linking Simulations andObservations
Aida Ahmadi1 , Rolf Kuiper2,1 and Henrik Beuther1
1

Max Planck Institute for Astronomy, Koenigstuhl 17, 69117 Heidelberg, Germany; 2 Institute of Astronomy andAstrophysics, University of Tuebingen, Auf der Morgenstelle 10, 72076, Tuebingen, Germany
E-mail contact: ahmadi at mpia.de
In the disk-mediated accretion scenario for the formation of the most massive stars, high densities and accretion
rates could induce gravitational instabilities in the disk, forcing it to fragment and produce companion objects. We
investigate the eﬀects of inclination and spatial resolution on observable kinematics and stability of disks in high-massstar formation. We study a high-resolution 3D radiation-hydrodynamic simulation that leads to the fragmentation ofa massive disk. Using RADMC-3D we produce 1.3 mm continuum and CH3 CN line cubes at diﬀerent inclinations.
The model is set to diﬀerent distances and synthetic observations are created for ALMA at ∼80 mas resolution and
NOEMA at ∼0.3”. The synthetic ALMA observations resolve all fragments and their kinematics well. The synthetic
NOEMA observations at 800 pc with linear resolution of ∼300 au are able to resolve the fragments, while at 2000 pc
with linear resolution of ∼800 au only a single structure slightly elongated towards the brightest fragment is observed.
The position-velocity (PV) plots show the diﬀerential rotation of material best in the edge-on views. A discontinuity
is seen at a radius of ∼250 au, corresponding to the position of the centrifugal barrier. As the observations becomeless resolved, the inner high-velocity components of the disk become blended with the envelope and the PV plots
resemble rigid-body-like rotation. Protostellar mass estimates from PV plots of poorly resolved observations are
therefore overestimated. We fit the emission of CH3 CN lines and produce maps of gas temperature with values in
the range of 100–300 K. Studying the Toomre stability of the disks, we find low Q values below the critical value forstability against gravitational collapse at the positions of the fragments and in the arms connecting the fragments
for the resolved observations. For the poorly resolved observations we find low Q values in the outskirts of the disk.
Therefore, despite not resolving any of the fragments, we are able to predict that the disk is unstable and fragmenting.
This conclusion is true regardless of knowledge about the inclination of the disk. These synthetic observations reveal
the potential and limitations to study disks in high-mass star formation with current (mm) interferometers. While theextremely high spatial resolution of ALMA reveals extraordinary details, rotational structures and instabilities within
accretion disks can also be identified in poorly resolved observations.
Accepted by Astronomy & Astrophysics
https://arxiv.org/pdf/1909.04051

A Radio Census of the Massive Stellar Cluster Westerlund 1
H. Andrews1 , D. Fenech2 , R.K. Prinja1 , J.S. Clark3 , and L. Hindson4
1

University College London, Gower St, Bloomsbury, London WC1E 6BT; 2 Cavendish Laboratory, JJ Thomson
Avenue, Cambridge CB3 0HE; 3 Open University, Walton Hall, Kents Hill, Milton Keynes MK7 6AA; 4 University of
Hertfordshire, Hatfield, Hertfordshire, AL10 9AB
E-mail contact: holly.andrews.16 at ucl.ac.uk
Context. Massive stars and their stellar winds are important for a number of feedback processes. The mass lost in thestellar wind can help determine the end-point of the star as a NS or a BH. However, the impact of mass-loss on the
post-Main Sequence evolutionary stage of massive stars is not well understood. Westerlund 1 is an ideal astrophysicallaboratory in which to study massive stars and their winds in great detail over a large range of diﬀerent evolutionary
phases.
Aims. We aim to study the radio emission from Westerlund 1, in order to measure radio fluxes from the populationof massive stars, and determine mass-loss rates and spectral indices where possible.
Methods. Observations were carried out in 2015 and 2016 with the Australia telescope compact array (ATCA) at 5.5
and 9 GHz using multiple configurations, with maximum baselines ranging from 750 m to 6 km.
Results. 30 stars were detected in the radio from the fully concatenated dataset, 10 of which were WRs (predominantly
late type WN stars), 5 YHGs, 4 RSGs, 1 LBV star, the sgB[e] star W9, and several O and B supergiants. New source
detections in the radio were found for 5 WR stars, and 5 OB supergiants. These detections have led to evidence for 3
new OB supergiant binary candidates, inferred from derived spectral index limits.
Conclusions. Spectral indices and index limits were determined for massive stars in Westerlund 1. For cluster
members found to have partially optically thick emission, mass-loss rates were calculated. Under the approximation ofa thermally emitting stellar wind and a steady mass-loss rate, clumping ratios were then estimated for 8 WRs. Diﬀuse
radio emission was detected throughout the cluster. Detections of knots of radio emission with no known stellar
counterparts indicate the highly clumped structure of this intra-cluster medium, likely shaped by a dense cluster wind.
Accepted by A&A
http://arxiv.org/pdf/1909.04339

http://arxiv.org/pdf/1909.09476

What is the physics behind the Larson mass-size relation?
J. Ballesteros-Paredes1 , C. Román-Zúñiga2, Q. Salomé1 , M. Zamora-Avilés3 and M.J. Jiménez-Donaire4
1

Instituto de Radioastronomı́a y Astrofı́sica, UNAM, campus Morelia. PO Box 3-72. 58090. Morelia, Michoacán,México; 2 Instituto de Astronomı́a, UNAM, campus Ensenada. Ensenada, Baja California. 22860. México; 3
CONACYT-astronomw69(e)-1.7(d)-300.2(p0.u92.05960.809cmBT/Tc4191Tf6.95-5.9(0)-5.9(.)i)3(ze)Tf/Tc4191Tf25(t)f6 0xico;