星形成ゼミ・報告 (SFN #307 N.21-30)資料
2018年8⽉3⽇

古屋玲(徳島⼤学・教養教育院)

Accepted
byfor
ApJof theexample,the wavelength-dependentux ratio.
Within theThe
consideredX).
Wedisk,reporton the distances,kinematics, and apocenter-to-pericenter
ages of the groups within
the Complex.
Orion Dparametergroups is inspace, theof theOnmaterial
strengthon Orion
the appearance
is stronger
than that ofIndynamical
processof impact
expanding.
the otherhand,
B is stillofinthe
thediskprocessof contraction.
λ Ori theexcitation
proper mot
http://arxiv.org/pdf/1806.11127
of thesystem. Finally,findexpansionthat the impact
theexplosion
collisional fromparameterson the net
energyisareconsistent
with a weradialdue toof ana supernova;
thespectral
tracebackagedistribution
from the expan
weak. the age of the youngest stars formed near the outer edges of the region, and their formation would have b
exceeds

紹介しない論⽂
21

Impactofplanetesimaleccentricities
and material
strength
onpositions.
the appearanceof eccentriggered
when
they were half-way
from the cluster
center to theircurrent
We also present
a comparAccepted by
A&A
tric
debrisdisks
between the parallax and proper motion solutions obtained by Gaia DR2, and those obtained towards star-form
https://arxiv.org/pdf/1806.02391
1
MinjaeKim, Sebastian
Wolf1Array.
, Torsten Löhne3 , Florian Kirchschlager1,2 and Alexander V. Krivov3
regions by
VeryLong Baseline
122

Institut für
Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, Leibnizstraße 15, 24118
Acceptedby Theoretische
AJ2

From
Planetesimalto Planet
Turbulent
Disks. II.
Formationof GasGiant
Planets
Kiel,
Germany;
Departmentof Physicsin
andAstronomy, University
CollegeLondon, Gower
Street,London,WC1E
https://arxiv.org/pdf/1805.04649
6BT,
UnitedKingdom;1 ,3Hidekazu
Astrophysikalisches
Hiroshi
Kobayashi
Tanaka2Institut und Universitäts-Sternwarte, Friedrich-Schiller-Universität Jena,
Schillergäßchen
2-3, 07745 Jena, Germany
1
Department of Physics, Nagoya University, Nagoya, Aichi 464-8602, Japan; 2 Astronomical Institute, Tohoku UniE-mailmkim
at astrophysik.uni-kiel.deversity,contact:
Aramaki,Aoba-ku,
Sendai
980-8578,
Self-Stirringof DebrisDiscs
by Japan
Planetesimals Formed by Pebble Concentration
Acceptedby MNRAS
Context.
SinceV.circumstellar
dust
in debrisdisks1is short-lived, dust-replenishing requires the presence of a reservoir
E-mail contact:
hkobayasnagoya-u.jp
Alexander
Krivov1atand
Mark
Booth
http://arxiv.org/pdf/1806.05431
of planetesimals. These planetesimals in the parent belt of debris disks orbit their host star and continuously supply
1In the core accretion scenario, gas giant planets are formed form solid cores with several Earth masses via gas
Astrophysikalisches
Friedrich-Schiller-Universität Jena, Schillergächen 2-3, 07
thedisk with fine dust Institut
through undtheirUniversitätssternwarte,mutual collisions.
accretion.
We
investigate
theformation
of
such
cores
via
collisional
growth from kilometer-sized planetesimals in
Jena,
Germany
Aims.
We
aim
to
understandeﬀectsofdiﬀerent
collisionalparametersonthe inobservational
appearance ofdisc
eccentric
Suppression
atmospheric
recyclingof planets
embedded
aandprotoplanetarybyare
turbulent disks. ofThestirring by forming
cores induces
collisional
fragmentation
surrounding planetesimals
debrisdisks. barrier
These parameters
are the eccentricity of the planetesimal belt, dynamical excitation, and the material
buoyancy
E-mailastro.uni-jena.deground contact:
down untilkrivov
radialatdrift.
The core growth is therefore stalled by the depletion of surrounding planetesiamls due
strength.
1
2The collisional strength of planetesimals determines the planetesimalto collisional
fragmentation
andlosesradialdrift.
Hiroyuki
Kurokawa, Takayuki
Tanigawa
Whena protoplanetary
disc
gas,
it leavesbehind planets and one or more planetesimal belts. The belts
is
1depletion timescale, which is prolonged for large planetesiamls. The size of planetesiamls around growing cores
dynamically
excited,either byplanets(‘planetstirring’) or2-12-1
by embedded
planetesimals(‘self-stirring’).
Earth-Life Science
Institute,Tokyo
Instituteof Technology,
Ookayama,big
Meguro,Tokyo 152-8550,
Japan; 2 Collis
Modellingthestructureof College,
star clusters
withfractional
Brownianmotiondeterminedby thesize distribution
atthe20onsetHagisho,of runaway
growth. Iwate
turbulence
delays the
National
Instituteof planetesimalTechnology,
Takanashi,
Ichinoseki-shi,
021-8511,
Japan
betweenplanetesimals
become Ichinoseki
destructive
and start
to produce
dust,
creating
anStrong
observabledebrisdisc. Follow
onset of runaway
growth,resultinginlarge
planetesimals.
Therefore,
the
core
mass
evolution
dependsonturbulent
11
1
O. Lomax,hiro.kurokawa
M. (2008),
L. Bates
and assumed
A. P. Whitworth
Kenyon& Bromley
itatiselsi.jp
oftenthat self-stirring
starts to operate as soon as the first ∼1000 km-s
E-mailcontact:
parameter α; the formation of cores massive enough without significant depletion of surrounding planetesimals needs
embedded‘Plutos’
formed.
However,state-of-the-art
pebbleconcentration
modelsrobustly
predict
planetesim
1−3−3
strongturbulence
ofhaveα and>
10.
However,thestrongturbulence
with
α
>
10
leads
to
a
significant
delayof theSchoolofofPhysics
Astronomy,
Cardiﬀ
University,
Cardiﬀ
CF24
3AA,
UK
The
ubiquitysuper-Earths
posesaproblemforplanetformation
theorytoexplainhow
they
avoidedbecoming∼∼
betweena few
kmgrowthand ∼200km envelopein sizeform
in of
protoplanetary
discs
rapidly,slowlygrowing
into Pl
onset
of runaway
and
theto
formation
massivecoresinwithin
the diskbefore
lifetime.
The
formationof coresgas
giants.
Rapid
recyclingof prevents
thegasof planets
embeddeda protoplanetary
discthenhas
been
proposedtoE-mailcontact:
oliver.lomax
at astro.cf.ac.uk
sizedbodies.
Weand
showthat thetimescale,
which
these
planetesimals
excitethe disc suﬃciently
for fragmentat
massiveenough
withinseveralmillions
years
therefore
requiresthe severalandtimes
enhancement
the solid
surfacedelay
thecooling
followingaccretionofdiscongas.
We compare
isothermal
non-isothermal
3Dofhydrodynamicalisshorterthanformation
ofmolecular
Plutos.
Using
an
model
based
the recycling
Ida & them
Makino(1993)
simulationsof thegas
flowsubstructure
past
a planet
toinvestigate
on quantified
thefeasibility
ofcomparing
themechanism.
densities,
which
isachievedin timescaletheinnerindisk<
dueinfluence
to analytic
pile-upofdrifting
dust
aggregates.
In
addition,
the theThe
degreeofthe
fractalclouds
can
be
byon
with
Fractio∼ 10 AUthe−1∗∗ enters
7−3/2
backedupbynumerical
integrations,
we
find
the
excitation
timescale
to
be
T
≈
100x
M
ag3−1Myr,
Radiative
coolingis
implemented
by
using
the
β
coolingmodel.
We
find
that,
in
either
case,
gas
the
collisional
strengthQ
evenforkilometer-sizedorsmallerbodies
aﬀectsthegrowthofcores;
Q>
10
ergBondi
for whexcitem⋆D
D ∼Motion (FBM) surfaces
or volumes. These fields are self-similar over all length scales
andcharacteri
sphereathighleavestheregions,or units
vice versa
disc gas rotates
sub-Keplerian.
xbodiesa protoplanetary
discmidplane
progenitor
in theof thewhen
Minimum-Mass
Solar
Nebula, a its ra<
kmlatitudes
ismasslikelyofandfor
thisgasthroughgiant formation.
m is the∼ 1total
exponentH,
which
describes
thestructuralroughness.
Given
that
the
structureofmolecular
clouds a
However,
incontrasttotheisothermal
case
where
the
recyclingflow
reachesthedeeperpartof
theenvelope,theinflow
the unitsof
100 AU,M⋆ isthe stellar mass in solar masses. These
areV-VIのYSOs
applied to a setof 23 debris dGaia in
DR2を使った論⽂
̶and#23:
Orionクラスターの3次元構造,#30:results
Lupus
disks
Accepted
byof
ApJ
structurestarclusters
arealmostcertainly
linked,itwouldbeadvantageous
to
also
apply
this analys
isinhibitedfrom reaching
the deepenvelope
non-isothermalcase.theOnce
the atmospherestarts arecooling,buoyant
thathave been
well resolved
with
ALMAinorthe
SMA.
We find thatmajorityof these discs
consistent
with bhttp://arxiv.org/pdf/1806.07354
ALMA連続波データを使った論⽂
̶ discs#26:
CMF
in IRDCs,
#28:
class
II円盤サーベイ
towards
Cha.I
Currently,
thestarclusters
is oftenquantified
by atmosphere.
applying
QWe
analysis.
Qvaluesfromobservforce
preventsHowever,the structurehigh-entropy
disc
gas
from
intrudingthelow-entropy
suggestthe buoyancy
self-stirred.
three oflarge
aroundyoung
early-typestars
do require
planets
as thatstirrers.
These
are
49 C
barrier
isolates by
the lower
envelopethemfrom withthe recycling
furtherclusters.
cooling, whichmayleadrunaway generated
gas accretionusing
interpreted
comparing
those
from
artificial
These
are
typicallyHD
95086,
andHR
8799,
of whichthelattertwoandareallows
alreadyknown
to haveplanets.
理論論⽂
̶
⼤質量近接連星系形成における磁場の役割
onto
theor
core.
(BF)
Radial Density Profile (RDP) model. We present a single cluster model, based on FBM, as

24
25

27

紹介する論⽂

23

The APOGEE-2 Survey of the Orion Star Forming Complex II: Six-dimensional strucAccepted
MNRAS Here, the structure is parameterised by H, and the standard deviation of the log-su
to thesebymodels.
ture

23

The APOGEE-2 Survey of the Orion Star Forming
Complex II: Six-dimensional strucN
N
ture
↵

(deg)

vr

(deg)

(km s

v↵

1

)

(mas yrv

1)(mas yr

1)⇡

AgeCM D

AgeHR

(mas)

(Myr)

(Myr)

ingroup

AP OGEE

1
1 (18)
2
2
(13)
(14)
(15)
(16)
(17)
(20) , Carlos
(21)
(22)
MarinaKounkel, Kevin
Covey, Genaro(19)Suárez
Román-Zúñiga, Jesus Hernandez2 , Keivan
0.54
0.67
1.44
0.29
0.35
0.086
1.9
1.6
104
29
3
3
4
5
6

Stassun, Karl, EricFeigelson, KarlaPeñaRamı́rez, Alexandre Roman-Lopes , Nicola
0.47
0.51
1.60O Jaehnig
0.37
0.23 D.0.084
1.1
1.1
25
15
7
8
2.85S Stringfellow
0.18
0.16
6 10,11 , José G. Fernández-Trincado12,13 ,Da0.37
Rio0.65, Guy, J. 0.061
Serena1.9Kim9 ,1.1Jura 16
Borissova
0.09
0.22
0.19
0.72
0.38
0.196
1.6
1.9
11
11
Adam Burgasser14 , D. A. Garcı́a-Hernández15,16 , Olga Zamora15,16 , Kaike Pan17 and Christian Nitschelm5of Physics and Astronomy, Western Washington University, 516 High St, Bellingham, WA 98225;
背景, Department
観測

Only a portion
1 shown here. Full table is available in an electronic form.
a lsr

2

Instituto de Astronomı́a, Universidad Nacional Autónoma de México, Unidad Académica en Ensenada, Ensenada

1. Apache Point Observatory Galactic Evolution Experiment (APOGEE) 分光サーベイ@1.5-1.7 micronb Heliocentric

2. APOGEE gives (α, δ, vr), GAIA does (α, δ, vr, π, vα, vδ) → 6D info.
21

解析
1. 分光データから星の諸元(有効温度, 重⼒加速度, 半径, 輻射等級)と運動学的諸元(絶対位置, 視線速度)を導出.
2.GAIAデータと他の測距デー
タ(HipparcosとVLBAによる固有運動)との整合性確認
3.HR図
4.APOGEEとGaiaのカタログマッ
チング
5.クラスター解析

Figure 11. Distribution of stars identified as members Orion A (green), Orion B (orange), Orion C (cyan), Orion D (red), andOri (blue). In the first panel, black dots show the position of the major bright stars in Orion.

結果[左の図]
⽮印は, 各クラスターの系統運動差引後の1.2 Myrスパンでの固有運動の⼤きさと⽅向, ⿊丸は主な星各星団の距離は,390̶440 pc
星団の年齢も,
1 ̶12Myrと幅広い.

議論
Ori A:Ori B: still contracting
Ori C:Ori D: expanding
λ Ori: SN爆発による
radial expansionから期待される運動と整合

DR2 view of the Lupus V-VI clouds: the candidate diskless young stellar objects
30 Gaia
are mainly background contaminants
Carlo F. Manara1 , T. Prusti2 , F. Comeron1 , R. Mor3 , J.M. Alcalá4 , T. Antoja3 , S. Facchini5 , D. Fedele6 ,A. Frasca7 , T. Jerabkova1 , G. Rosotti8 , L. Spezzi9 and L. Spina10
1 動機
背景,
European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany; 2 ScientificSupportOﬃce, Directorate of Science, European Space Research and Technology Centre(ESA/ESTEC), Keplerlaan 1,
1. ⼀般に,前主系列星の進化に伴い付随する円盤の質量は指数関数的に低減する(e.g.,
Haisch+01).
3
2201
AZ
Noordwijk,
The
Netherlands;
Institutde Ciéncies del Cosmos, Universitat de Barcelona (IEEC-UB), Martı́
Fig. 2. Proper motion of the Gaia targets in the fieldof view of the4
2. Spitzerによる探査では,
disk
fraction= 15%
towards
Lupus
V
and
VI.
これはLupus
I-IIIでのage= 16,
2–380131i Franqués
1, highlighting
E-08028 Barcelona,
Spain;
INAF-Osservatorio
Astronomico
diCapodimonte,
via MoiarielloManaraet al.:
Lupus
V-VI
with
Gaia
DR2
Lupus
V region,the candidate
young stellar
objects with
Napoli,
Max-Planck-Institut
Extraterrestrische
Physik, Giessenbachstrasse 1, 85748 Garching bei München,redcircles,Italy;
and the5 fiveconfirmed young starsfürwithcyan circles.
MyrsのYSOでの検出率50%に⽐べ有意に低い.
6
Germany; INAF-Osservatorio Astrofisico di Arcetri, L.go E. Fermi 5, 50125 Firenze, Italy; 7 INAF-Osservatorio
解析
Astrofisico di Catania, via S. Sofia, 78, 95123 Catania, Italy; 8 Institute of Astronomy, University of Cambridge,
et al.: Lupus
9 with Gaia
200
pc, are classified
as Class IIManara
bySpezziet UK;
al.V-VI(2011),
andDR2
thatOrganisation for the Exploitation of Meteorological Satellites
MadingleyRoad,
Cambridge
CB30HA,
European
1. Gaia固有運動データ(下図)から距離決定→
⾊等級図(CMD;
右図)で進化段階を推定
theremainingoneisclassified
as
Class
III.
This
classificationis10(Eumetsat), Eumetsat Allee 1, 64295 Darmstadt, Germany; Monash Centre for Astrophysics, School of Physics andconfirmed also by Dunham et al. (2015), and none of these five
Astronomy, Monash University, VIC 3800, Australia
targets are flagged as likely being AGB contaminants.
結果These fiveE-mailhave
contact:
cmanaraeso.orgof 6.662±0.013 mas, corobjects
a weighted
meanatparallax
responding to a mean distance of ⇠150 pc. If1.theGaiaデータ：Lupus
Lupus clouds
V andExtensive surveys of star-forming regions with Spitzer have revealed
populations of disk-bearing young stellar objects.
are at 150 pc (e.g., Comerón 2008), then three VIとされる天域内の星はof these targets
These
have
providedcrucialthe timescaleof dispersal of protoplanetary disks, obtained by carefullyarein thecloud,
while oneis in constraints,
front of it andsuch
one asbehindit.
combining infrared data with spectroscopic39+44=83天体
or X-ray data. While observations in various regions agree with the general
To further investigate whether the closer YSO candidates aretrend offrom
decreasing
disk fraction
with
the
Lupus
V and VI regions appeared to have been at odds, having andi↵erent
the backgroundobjects,
we age,
show
in
Fig.
2
the
2.CMDからYSOsは5天体のみextremely
lowfordisk
Here weinshow,
using V
thecloud.
recent Gaia data release 2 (DR2), that these extremely low disk
propermotionthefraction.
YSO candidates
the Lupus(残り78は⾚⾊巨星)
fractionsdue with
to a parallaxes
very high larger
contamination
Fourout ofaretheactually
five objects
than 5 masby background giants. Out of the 83 candidate young stellar
objects(YSOs)atinµ⇤↵theseGaia, andonlythefive have distances of ∼150 pc, similar to YSOs in the otherare
all clustered⇠ 9clouds
mas/yr,observedµ ⇠ 25bymas/yr,
3.分⼦雲の距離を150
pcとする
last
one clouds,
has µ⇤↵ ⇠and20have
mas/yr,µ ⇠ proper
34 mas/yr.
Theseverymembers in this star-forming complex. Of these five targets,
Lupus
similarmotions
toare
other
ならば,
3天体のみがLupusVdi↵erent
valuesfrom thosethe bulk
the candidate
YSOs,
four have
optically
thick of(ClassII) ofdisks.
On the one
hand, this result resolves the conundrum of the puzzling low⇤
which
are foundintothesehave µmas/yr,onµ the⇠VIに付随するYSOs.
2 mas/yr,
the it further clarifies the need to confirm the Spitzer selected↵ ⇠ 2while,
disk fraction
clouds,
other
hand,
same
parameter
space withas mostof tracers,
the Gaia especiallytargets in thefield at low galactic latitude like Lupus V and VI. The use of
diskless
populationotherin regions
注：この図ではofview,
which are ismainly
backgroundobjects.
Thedi↵erence
4.⾮常に低い星形成率.
Gaia
astrometry
now anindependentandreliableway to further assess the membership of candidate YSOs in these,星団の系統運動のin the proper motion space of these closer YSO candidates sugand potentially other, star-forming regions.
gests that they are a homogeneous group that is kinematically Fig. 3. Absolute magnitude vs color for the candidate YSOs in the Lu速度は引いていない.

Fig. 2. Proper motion of the Gaia targets in the field of view of thepus Vwith(top) and Lupus VI (bottom) regions with positive parallax anddistinctfrommore
objects.
This
that they
Accepted
bythe
Astronomy& Astrophysics
Letters
Lupus distantV region,
highlighting
theconfirms
candidate youngstellar objects
available Gaia magnitudes. Only the four confirmed young objects incircles,and population.
the five confirmed
youngstars with cyan
most likely belong red
to thecloud
Whencomparingthe circles.

Fig. 2. Propermotion of the Gaia targets in the field of view of thehttps://arxiv.org/pdf/1806.04943
propermotion values
for thefiveclose-bytargets with those of
Lupus V region, highlighting
the candidate
youngstellarobjects with
red circles,
and thefive confirmed
younginstars
cyan circles.
otherconfirmed
YSOs
thewithLupus
complex (López Martí, et al.

Lupus V with available Gaia magnitudes have color and magnitudes
compatible with age<10 Myr, according to the overplotted extinctionfree
200 pc, are classified as Class II by Spezzi et al. (2011),
andisochrones.
that

28

An ALMA Survey of faint disks in the Chamaeleon I star-forming region: Why aresome Class II disks so faint?
Feng Long1,2 , Gregory J. Herczeg1 , Ilaria Pascucci3 , Daniel Apai3,4 , Thomas Henning5 , Carlo F.
Manara6 , Gijs D. Mulders3 , László. Szűcs7 and Nathanial P. Hendler3
1

背景,Kavli
観測 Institute for Astronomy and Astrophysics, Peking University,3 Beijing 100871, China; ;2Department of
Astronomy, School of Physics, Peking University, Beijing 100871, China; Lunar and Planetary Laboratory, University
1. ALMA
850 micronでのClassII objects
円盤探査(Pascussi+16)から,ofCha
Iの2-3Myr-oldのclass
II天体5 Maxof Arizona,
Tucson, AZ 85721,
USA; 4 Steward
Observatory,
University
Arizona,Tucson, AZ 85721, USA;
Planck“dustInstituteformass”,
Astronomy,
Germany; 6 European Southern Observatory, Karl-Schwarzschild-Str. 2,
において,
disk
MdustHeidelberg,と星質量M*の相関が知られていた。本研究は、その発展。
D-85748 Garching bei München, Germany; 7 Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1,
2. ALMA
at 850
micronGermany
連続波, ⾓度分解能~1”
D-85748
Garching,
E-mail contact: longfeng at pku.edu.cn
ALMA surveys of nearby star-forming regions have shown that the dust mass in the disk is correlated with the stellar
mass, but with a large scatter. This scatter could indicate either diﬀerent evolutionary paths of disks or diﬀerent
initial conditions within a single cluster. We present ALMA Cycle 3 follow-up observations for 14 Class II disks thatwere low S/N detections or non-detections in our Cycle 2 survey of the ∼ 2 Myr-old Chamaeleon I star-forming region.
With 5 times better sensitivity, we detect millimeter dust continuum emission from six more sources and increase thedetection rate to 94% (51/54) for Chamaeleon I disks around stars earlier than M3. The stellar-disk mass scaling
relation reported
Pascucciimages
et al. at(2016)
is forconfirmed
with these
updatedmeasurements.
outliersin the Fmm –Figure 1. inContinuum
887µm
Cycle 3 sample,
orderedby decreasing
millimeterFaint
flux withcolormap
00 ⇥ M⊕ andM∗ planescaled
includethree(CHXR71,
CHXR30A,
and T54)
with atdust
masscorner.
upperImages
limitsareof60.2by thepeaknon-detections
flux of each source.
Contour levels
for each panel
are labeled
the right
three very
(CHXR20,
ISO91,
and 00T51)
with
masses∼ 0.5
M⊕companions. By investigating
the SED
600faint
with disks
the typicalbeam sizeof 1.00 1⇥0.
7 shownin dustthe topleft panel.
Close
for CHXR79,
T27, morphology,
andaccretionT51
property
andwithstellarmultiplicity,suggestfor adopted
the threemillimeter
non-detections
that tidal interaction by
are marked
whitecrosses, withwe
positionanglesfrom
Daemgen etal. (2013).
解析
a close companion(<100 AU) and internal photoevaporation may play a role in hastening the overall disk evolution.
3
tainedofthe
the secondary
fitted parametersthat arebrighterthreethetimes
theuncertainty
5 and
1. 物理量へ:
⼲渉計visibilityデータをフィットし、位置,→M
The presenceof. aThe
diskuncertainties
around only
star inサイズ、フッラクス密度を推定
a binarysystemmaythanexplainobserved
diskへstellar SEDs
scaledthe squareroot of the reduced 2 ofand located near the expected source position are
low disk aremassesforby
somesystems.
Table
SourceProperties
the fit. The fitted fluxes
and2.phasecentero↵sets and Measured
considered Fluxes
detections. The median values of ↵Accepted by ApJ
are consistent within the uncertainties for both the= 0.00 34 and= 0.00 02 from the detections
https://arxiv.org/pdf/1806.04826
Gaussianand the point-source
areFconsistent
within Pascucci
2MASS ellipticalName
Multiplicity
SpTy log(Mmodels.
Fmm (P16)↵ the values reported
FWHM
log(Mdust )⇤)mm
Of the 14 observed sources in our Cycle 3 proet al. (2016) in the full sample. These o↵sets from(arcsec)
(M )
(mJy)
(mJy)
(arcsec)(arcsec)(arcsec)(M )連星間隔はこの観測(visibility andgram, 11 are detected with a signal-to-noise ratio
the 2MASS coordinates are roughly consistentmap)から測定しているらしく,
of >3. Table
2 summarizes
the measured
conwith(7)expectations(Lopez
(1)
(2)
(3)
(4)
(5)
(6)
(8) based on(9)proper motion
(10)
(11)
検出最⼩スケールは(天球⾯でtinuum flux densities and associated uncertainMartı́ et al. 2013; Murphy et al. 2013).
~100AUとの記述あり.
J10533978-7712338
M2-0.41 in 4.60±0.79-0.47±0.02-0.04±0.01
ties (Fmm ), o↵sets from the phasecenterright 24 3.74±0.16
Three sources
remainundetected. For these0.24

830AU 300AU

Long et al.

参考:
単独星

今回の上限値

Figure 3. Left: Continuum flux densities as a function of stellar mass. The 14 sources re-observed in Cycle 3 areshown3.in orange,
while the othersflux
are shownin blue
fluxes adopted
from Cycle
2 observations(Pascucci re-observed
et al.
FigureLeft: Continuum
densities
aswitha functionof stellar
mass.
The 14 sourcesin Cycle 3 are2016). Open circles for detections and downward triangles for non-detections. The best fit relation (orange full line)howninorange, while the others are shown in blue with fluxes adopted from Cycle 2 observations (Pascucci et al.
using結果と議論
updated fluxes and upper limits are highly consistent with relation (almost overlapped thus not shown here) from
016).
Open
detections
and downwardfor
The best
fit relation(orange full line)
Pascucci
et al.circles(2016). for
Revisedrelation without
considerabletriangles
outliers (seetextnon-detections.
for how they are selected)
is shownin
1. 本研究の動機となったM
dust vs. M*相関
dottedline. The
medianerror
bars forlog(Marelog(Fmm) are shownwith
in therelation
left upper(almost
corner andoverlappedcorrespond tothus
0.1 not shown here) fromsing
updatedfluxesandupperlimitshighlyconsistent⇤ ) anddex(Fig.3)は⼤筋で確かめれたが,and 0.05 dex; Right: Distribution of o↵setsscatterは⼤きfrom data points to the fitted line. O↵sets in positive represent sources
Pascucci
et al. (2016). Revised relation without
considerable outliers (see text for how they are selected) is shown inwithくなった.
higher continuum
fluxes.
FittedparametersfortheGaussiandistribution are labeled in text. The non-detections
本論⽂では,
best-ﬁtからの残差の
otted
line.
The
median
error
bars
for
log(M
)
and
log(F
shown
inCyclethe left
upper corner⇤mm ) areandare shown in hatches to separate from the detections shownin full histogram,the three
3 non-detections
are and correspond to 0.1
要因(e.g.,中⼼星輻射による光
exshownand0.05
dex;潮汐相互作⽤,
Right: Distributionof o↵sets from data points to the fitted line. O↵sets in positive represent sourcesin orange.

Figure 7. millimeter flux densities as a function of projected binary separation. Single stars are shown in therighthatchedregionfor reference.
three Hot sam蒸発)をSED解析にもとづき議論.
withthese
higherFitted parameters
the Gaussian
distribution
are labeled
in text. The The
non-detections
faintcontinuum
disks to the fluxes.
entire Chamaeleon
I (略)sam- forFigure6)8 , indicatingthat any on-goingaccretionpleinThe
non-detections
arehighlighted
in orange downward
re ple,shown
in hatches
theitsdetections
fulluncertainties
histogram,inandthe threeareand thenattempt toto separate
place eachfrom
disk onown
isshown
weak.
accretion
rateCycle
are 3 non-detections
2. 連星間隔と850
evolutionary
track basedmicronフラックスの関係
on source properties.
typically⇠0.3 dex andare twomore verticaluncertain nearhown
in orange.
triangles.
The
gray dashed lines represent
9As
a parallel e↵ort to understand young stellar
the chromospheric boundary . The other two faint(Fig.7)で、30AU-300AUの範囲でフラックス
830CHXR20
AU
and300
AU, withas thatproposedin Harris
et al. (2012)
hese
faint
disks Manara
to the etentire
Chamaeleon
Figure, indicating
any on-goingaccretionsystemevolution,al. (2016,2017) mea- I samsources,and6)T51(markeda downがCha Iでは優位に低減しない(Taurusでは低
rates
for mosteachsourcesin ourward arrowin6), havecontradictoryaccre-inple,sured
andmass
thenaccretionattempt
to7 placedisk
on its own
is Figureweak.
The
uncertainties
accretion
are bar for
to grouptheTaurussample.
The
medianrate
error
減; Harris+12).
→ 周連星円盤の寿命を決め
ALMA
Cycle 2 Chamaeleon
disk survey (Pasmeasurements in the literature but are esvolutionary
track based onI source
properties. tion rate
typically⇠0.3 dex
dex andand shown
are more
uncertain
near corner.
log(F
)
is
0.05
in
the
left
lower
mm
cucci
et
al.
2016),
basedon
UV
continuum
extablishedby
X-Shooter
spectratobeaccreting(e.g.
る環境要因の違いの視点から精査必要.
9As
a orparallele↵ort whento understandthe2016,chromosphericboundarycess,line luminosity
signal-to-noiseyoung
ratio stellar
Manara et al.
2017). Meanwhile,
the vast. The other two faintCore Mass Function Across Galactic Environments.
26 TheClumpsII. Infrared Dark Cloud

Mengyao Liu1 , Jonathan C. Tan1,2 , Yu Cheng3 , Shuo Kong4
1

背景,Dept.
観測 of Astronomy, University of Virginia, Charlottesville, Virginia3 22904, USA;2

Dept. of Space, Earth &Environment, Chalmers University of Technology, Gothenburg, Sweden; Dept. of Astronomy, University of Florida,
4
1. Clump
surveyFlorida
towards
seven
IRDCs
w. of
ALMA
at 1.3mm
連続波, 各視野は27”,
Gainesville,
32611,USA;
Dept.
Astronomy,
Yale University,
New Haven,LAS=11”,
CT 06511, ACAなし
USA
E-mail fromcontact:
ml7hc
at virginia.edu
2. SelectedIRAC
8 micronextinction maps, 距離 2.4 to 5.7 kpc

We study the core mass function (CMF) within 32 dense clumps in seven infrared dark clouds (IRDCs) with the
Atacama Large Millimeter/submillimeter Array (ALMA) via 1.3 mm continuum emission at a resolution of ∼ 1′′ .
We have identified 107 cores with the dendrogram algorithm, with a median radius of about 0.02 pc. Their masses
range from 0.261 to 178 M⊙ . After applying completeness corrections, we fit the combined IRDC CMF with a powerlaw of the form dN/d log M ∝ M −α and derive an index of α ≃ 0.86 ± 0.11 for M ≥ 0.79 M⊙ and α ≃ 0.70 ± 0.13
for M ≥ 1.26 M⊙ , which is a significantly more top-heavy distribution than the Salpeter stellar initial mass function(IMF) index of 1.35. We also make a direct comparison of these IRDC clump CMF results to those measured in
the more evolved protocluster G286 derived with similar methods, which have α ≃ 1.29 ± 0.19 and 1.08 ± 0.27 inthese mass ranges, respectively. These results provide a hint that, especially for the M ≥ 1.26 M⊙ range wherer & Tan2012). We
also evaluate
themore early-stage
than half environmentsof the cores ofareIRDC
associatedwithbemcompletenesscorrections
are modest,
themean
CMF inHhigh pressure,clumps may+ 1 ). The dotted
top-heavycompared
to images
thatnH,cinof themoreevolved,globalenvironment
of
the
G286
protoclusters.
However,largerFigure2. 1.3 mm
30
towardIRDC
dense
clumps(colorbar
in
Jy
beam
circlenumberdensityincontinuum
the cores,⌘pointings
Mc /(µV),
lineemission,e.g.,ND(3-2), DCN(3-2),
DCOH2
in eachpanel denotes
primarybeam.
The synthesized
beamareis shownbottomleft cornereach panel.
samplesof corestheprobing
these
diﬀerent
environments
neededbetterestablish
the ofrobustnessof Thethis corespotential
18 intotheµHidentified= 1.4m
is
the
mean
mass
per
H
assumingC
O(2-1)
and,occasionally,
SiO(5-4).
HowevebyH
the fiducial dendrogram algorithm are marked on the images, with red contours showing “leaf” structures.
CMF
variation.

0.1nH and V = 4⇡Rc3 /3. The mean value ofthe latter of these transitions is known to be
Accepted
by
ApJ
解析
nH,c /cm 3 ) is 6.58, with a dispersion of 0.34.
tracer of outflows, especially from more massive
http://arxiv.org/pdf/1806.02213
Source extraction ̶ dendrogram method
m an1.inspectionof the molecular line data of thesestars. Analysis of the SiO emission will be prese
optically
dust we放射を仮定し,ただし,
cへ (表参照).
s, as2.物理量への変換:
presented by Konget al. thin(2017),
note that 強度Iから質量⾯密度Σ
a companion paper(Liu etal., inTd=20K仮定
prep.).
Table 1. Estimated physical parameters for 1.3 mm continuum cores
Source

A1c1

l

b

d

( )

( )

(kpc)

18.78746-0.28505

4.8

Ipeak
(mJy beam
1.11

1

)

S⌫ 23

Mc,raw

Mc

Rc

(mJy)

(M )

(M )

(0.01 pc)

0.714

0.501

0.949

1.29

⌃c
(g cm
0.380

nH,c
2

)

(106 cm
3.05

3)↵ = 1.24 ± 0.17 for M 0.79 M , however, we
havewhich correction
would also
take aa
whichdethe completenessis about
Figure 6. Combined dendrogram-derived CMF from obser10.
Dueto potential
uncertainties
associatedvationsresults,
of 30
positionscovering
dense2003).
clumps withinsevencided to focus on the lower resolution resolution
& Tan
The
fact
IRDCs.correction,
The blackashistogramshows
the original,
we discuss
below,
we will“raw”
considtop-heavy
CMF
indicagiven that the IRDCs span a range of distances
from
2.4
CMF. The blue histogram shows the CMF after flux corto red
twohistogram
mass thresholds,
i.e., cases
incl
rectiondownand theshows the final,“true” ofCMF
to 5.7 kpc, but with IRDC C at 5 kpc and IRDC
D
at thisthemainfactorresistin
after thenapplying
numberrecoveryfractioncorrection.
The
excludingmass
bin.
bars show Poisson counting errors. The black, blue and5.7 kpc contributing a large fraction of theerror
samplesoinshowintheseenvironments,
Next,
Figure
6, we
show
the
CM
red dashedlines
the best
power
law
fit combined
results for theendsample(M 0.79) of these
CMFs,
respectively.
entireof Mseven
IRDCs.
The
raw,offluxthat the average distance of the IRDC coreshigh-mass
is 4.4kpc.
some
combinationinand “true” CMFs (black, blue and red histog
netic
field
supportisprThus in the end the e↵ective linear resolutions結果
aresimspectively) are obtained by simple addition of
1. 全サンプルから求めたCMF(左のFig.6)補正によってilar (within about 15%)
for the average IRDC
core
Note
that IRDC
clum
alentandCMFs for eachindividual
IRDC. Notehigh-mass側の2. 2段階の補正[空間フィルターされたﬂuxのリカバリ]
Poissonreduced.heating
Note also,that achieved in G286.
Overall the mass sensitivities
areerrors aretranow
thermalof
ビンが増えるを⾏なったのち,
theretheare still著者らのベスト推定は⾚いフィット
tworadiative
empty bins feedbacknear 100 M from
andalso quite similar between the two observations
and(強調表⽰は報告者による)core more massive that this. At the low-masscompleteness correction factors are relatively modest,
at sevenasindividual
proposedin the mod
CMFs of the 議論(あまりない)と研究の⽅向性
IRDCs all have dleast for M 1.26 M .
expected
to=bedown to or belowis
thenotbin centeredon M
1M
Figure 6. Combined dendrogram-derived CMF from obser1. 類似天体の結果との⽐較
vations of 30 positions covering dense clumps within sevenis approximately
thedetection
thresholdCloevolvedstages
as ofrepr
IRDCs. The
histogram shows
the CONCLUSIONS
original, “raw”
alpha = 1.6 +/- 0.7 pre4. black
DISCUSSION
AND
farthest cloud. A.calized
heating of the
CMF. The blue histogram shows the CMF after flux corstellar CMF inan “true”
IRDC CMFor the raw, flux-corrected
andrectionandthe
red
histogramshows
thefinal,“true”
CMF
expected
to be higher
We have measured the CMF in a sample of about
30(Ohashi+16)
simple fitting we thenderive power law indiceafter then applying number recovery fraction correction. The
error
bars clumps,
show Poissoncounting errors.
The black,forblue
and and number
environments,
if
power
IRDC
includingaccounting
flux
0.79 M of ↵ = B.
0.50
± 0.10,0.49+/± 0.09
and 0.
alpha= 0.900.06
red dashed lines show the best power law fit results for therespectively.
For &
MLE,
we 2015).
derive ↵ CMF=At
0.61±0.
Tantherecoveryfactors.
simple fitting,we“mini-starburst”
inhigh-mass
endincompleteness(M 0.79 M ) of these
CMFs,With
respectively.
W43-MM(Motte+18)
rect
indication
if the loderived high-end power law indices of ↵ ' 0.86 ± 0.11
higher in the IRDC cl
for M 0.79 M and ↵ ' 0.70 ± 0.13 for M 1.26 M . 2. 著者は将来への課題を4点あげていsample, ii. 他の環境でlocalized
IRDC core t
An MLE analysis yielded similar values. These results る [i.iflarge
は？, iii. low-mass側もサンプル必
than in G286, th
indicate a CMF that is top heavy compared the standard 要, iv.higher
mass導出法の検討]
their masses. If this e
Salpeter distribution with ↵ = 1.35.

29 The formation of high-mass binary star systems
Kristin Lund1 and Ian A. Bonnell1

School of Physics and Astronomy, University of St Andrews, North Haugh, St Andre
背景, 1動機
1. 熱的不安定性による分裂だけで⼤質量連星をつくることは難しい[連星形成には, 2つの分裂素⽚間の距離が2RJはE-mail contact: kblg at st-andrews.ac.uk
離れていないといけない. e.g., RJは=104AU for 10-19 g cm-3 gas at 10 K] .

We develop a semi-analytic model to investigate how accretion onto wide low-mass bin
2.連星系の質量と連星間隔は⽐例する(e.g.,
Bate
Bonnell 1997),
連星の諸元は星団内の最⼤質量の星の質量やhigh-mass binary system.
The
key& ingredientis toallow mass accretion while limiting th
星団の諸元と関わっているという予測(e.g.,
Larson1982, Elmegreen
2000,など)
We envision this process as
being
regulatedby an external
magnetic field during infall.
collapse spherically with material →eitheraccreting onto the stars or settling in a disk.
3.⼤質量星の近接連星系形成は研究が進んでいない
磁気制動による余剰⾓運動量の外部への移送を組み込んだ準解析的モデルinitial [⾮理想MHD効果は組み込んでいない.]
conditions are needed6 forthe resulting binary to be both massive and close. W
K. Lund & I. A. Bonnell
what happens to the binary separation as a result, depends on the relative size of it
2 K. Lund & I. A. Bonnell
⺟体の分⼦雲コアが⼀様密度
⺟体の分⼦雲コアが⾮⼀様密度
回転のみ compared to the specific angular momentum of the binary. When we add a magnetic fie
回転のみ
to the system which is capableandof✓ stripping
the molecular cloud of some of its angular◆ 1/2 ✓
◆ 1/2
5Rg T
4
RJ = binaries.
⇡⇢ Our, results suggest that(2)easing the formation of high-massclouds in excess of
2Gµ3
larger, can easily form binary systems
withmassesexcess Rof
25 M⊙ and separations
回転＋乱流＋磁場
where ⇢ is the gas
density,
T is the gasin
temperature,g is thegas constant, G is the gravitational constant, and µ is thefields of order 100 µG (mass-to-flux
ratios of order 5).
回転のみ
mean molecular weight. Typical values of the Jeans mass and
回転＋乱流＋磁場
Accepted by MNRAS

radius are ⇡ 1 M and ⇡ 104 au corresponding to densitiesof 10 19 g cm 3 and temperatures of 10 K. To form a binary
system, two fragments would have to be separated by twice
their Jeans radius, such that there is a direct relationshipbetween the mass and minimum separation of the fragments

回転＋乱流＋磁場

http://arxiv.org/pdf/1806.07394
M⇤,T

DR2 view of the Lupus V-VI clouds: the candidate diskles
30 Gaia
are mainly background contaminants
Rsep /

Figure 1. Accretion of material onto a wide low-mass binary with(bottom) and without (top) the presence of a magnetic field. The
1
masses of the binary stars will increase in either case, but the final
separation of the stars is more likely to decrease if a magnetic field
7
has stripped the system of some of its angular momentum.

(3)

Uniform
cloud density= ⇢0 )
such that(a)for
reasonablegas(⇢ temperatures,
fragmentation(b) Non-uniform cloud density (⇢ / R 2 )canonly form
close
systemsvery
low masses
Figure4. Changein binarymass binaryand separation
duringwith
accretion.
Di↵erent
coloured lines correspond to placing the binary system indi↵erent
environments.
For
the
red
line
the
initialmassofthebinaryis10M, in every other scenario it is 2 M . The black horizontal(Bonnell & Bate 1994). If fragmentation of molecular clouds
line marks
separation of 1 au, below which binary
likely to merge.
Mcloud = 500 M , Rcloud =0.5 pc,4⌦cloud = 3 ⇥ 10 14 rad s 1 and
2 a the1 stars are
3 systems,
were
only
way
to
form
high-massclose
binaryB0 = 100 µG.
1 then typical4 separations
8 would be expected9 to be in the
105range of 10 to 10 au.
collapse. The black horizontal line marks a separation of 1
an Mb /s ⇡ 4300. For these simulations we have restricted
Binary hardening in a stellar cluster is an alternative

Carlo F. Manara , T. Prusti , F. Comeron , R. Mor , J.M. Alcalá , T. Antoja
A. Frasca , T. Jerabkova , G. Rosotti , L. Spezzi and L. Spina

⼤質量星連星系の質量(a)

⼤質量星連星系の⾓運動量(b)

⼤質量星連星の間隔(c)Figure 3. Change in binary mass, angular momentum and separation as consecutive shells of a uniformly dense and turbulent molecular
cloud collapses. The di↵erent coloured lines correspond to placing the clouds in magnetic fields of di↵erent strengths. Mcloud = 500 M ,Rcloud = 0.5 pc and ⌦cloud = 3 ⇥ 10 14 rad s 1 .

結果と議論

in this particular scenario. In this calculation we are treatreach 5 M and the binary separation is almost 10 au. In
ing1.図3.
the molecular
cloud ass(t-ta uniformly
dense full sphere,
other words,
this is not a close high-mass system.
In contrast,
相似座標[x=r/c
進化に伴い磁場の効果は明らか(=中⼼部0)]なので横軸は時間と読み替えた場合,
neglecting the empty central region within the initial aca magnetic field of 100 µG or more results in a binary massの⾓運動量はほぼ⼀定だが, 磁場が強ければ質量は増し続け,
連星系間隔は⼩さくなっている.)
cretion radius, corresponding to ⇠0.1% of the total radius.
exceeding 19 M with a separation of less than 0.12 au.
Assuming a uniform spherical distribution the moment of
It is clear from Figure 3 that adding a magnetic field
2.連星系諸元の磁場強度依存性とは,
inertia,I, in the rotational energy equation,荷電粒⼦の磁場結合の度合いのこと。外側へ移送される余剰⾓運動量のcan be written
makes it easier to form binaries with higher mass and smaller
1979などから⼿であたえている。
as ⼤きさは結局、電離度が決めている。今、電離度はElmegreen
separation.
The e↵ect of the magnetic field increases withincreasing field strength, and in the case of the strongest field
2
2
I = Mcloud Rcloud,(28)
strength, 500 µG, most of the gas accreted from the cloud is
3.上記に加え,同時に形成される⼩質量星の影響 (例えば, ⼩質量星の分⼦流が駆動する乱流)や「現実的な環境
5
stripped entirely of angular momentum. Figure 3(b) shows
and theenergy ratio simplifies to要因」が考慮されていないけれども（考慮されていないから？）、100μGあればR=0.6 pc, 1100Msunの
how nearly no angular momentum is being added to the1
2
3
⺟体雲から間隔10R
sunで星質量10 -10 Msunの連星が形成可能.
binary during accretion of material starting at radii larger
Rcloud⌦2cloud
Erot
=
.
(29)
than ⇠ 0.2 pc.