星形成ゼミ
The Star Formation Newsletter 329
1~7

徳田一起 (大阪府立大学/NAOJ)

1Dust clearing by radial drift in evolving protoplanetary disks

2

Radiative Transfer modeling of EC 53: An Episodically Accreting Class I Young
Stellar Object

3

The nature of the methanol maser ring G23.657−00.127. II. Expansion of themaser structure

4

Dynamical cloud formation traced by atomic and molecular gas

5Birth of convective low-mass to high-mass second Larson cores

6

GW Ori: Interactions Between a Triple-star System and its Circumtriple Disk in
Action7

Kinematics of T Tauri Stars Close to the Sun from the Gaia DR2 Catalogue

1

Dust clearing by radial drift in evolving protoplanetary disks
Johan Appelgren1 , Michiel Lambrechts1 , and Anders Johansen1
1Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, 22100 Lund, Sweden

E-mail contact: johan at astro.lu.se
Recent surveys have revealed that protoplanetary disks typically have dust masses that appear to be insuﬃcient toaccount for the high occurrence rate of exoplanet systems. We demonstrate that this observed dust depletion isconsistent with the radial drift of pebbles. Using a Monte Carlo method we simulate the evolution of a cluster ofprotoplanetary disks, using a 1D numerical method to viscously evolve each gas disk together with the radial drift ofdust particles that have grown to 100 µm in size. For a 2 Myr old cluster of stars, we find a slightly sub-linear scaling
between the gas disk mass and the gas accretion rate (Mg ∝ Ṁ 0.9 ). However, for the dust mass we find that evolved
dust disks have a much weaker scaling with the gas accretion rate, with the precise scaling depending on the age at
which the cluster is sampled and the intrinsic age spread of the disks in the cluster. Ultimately, we find that the dust
mass present in protoplanetary disk is on the order of 10–100 Earth masses in 1–3 Myr old star-forming regions, afactor of 10 to 100 depleted from the original dust budget. As the dust drains from the outer disk, pebbles pile up in
the inner disk and locally increase the dust-to-gas ratio by a factor of up to 4 above the initial value. In these highdust-to-gas ratio regions we find conditions that are favourable for planetesimal formation via the streaming instability
and subsequent growth by pebble accretion. We also find the following scaling relations with stellar mass within a
1–2 Myr old cluster: a slightly super-linear scaling between the gas accretion rate and stellar mass (Ṁ ∝ M⋆ 1.4 ), aslightly super-linear scaling between the gas disk mass and the stellar mass (Mg ∝ M⋆ 1.4 ) and a super-linear relation
between the dust disk mass and stellar mass (Md ∝ M⋆ 1.4–4.1 ).
Accepted by A&A
http://arxiv.org/pdf/2004.02918

Radiative Transfer modeling of EC 53: An Episodically Accreting Class I Young Stellar
原始惑星系円盤のダスト質量は小さいのではないか？(=>系外惑星を説明でき
Object1
2
ない？)
小石(pebble)のradial
driftで説明できる
Giseon Baek
, Benjamin A. MacFarlane, Jeong-Eun
Lee1 , Dimitris Stamatellos2 , Gregory Herczeg3 ,Doug Johnstone4,5 , Carlos Contreras Pena6 , Watson Varricatt7 , Klaus W. Hodapp7 , Huei-Ru Vivien
Chen8 and Sung-Ju Kang9
School of Space Research and Institute of Natural Sciences, Kyung Hee University, 1732 Deogyeong-daero, Giheunggu, Yongin-si, Gyeonggi-do 446-701, Korea; 2 Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy,
1

3

2

Radiative Transfer modeling of EC 53: An Episodically Accreting Class I Young Stellar Object

Giseon Baek,1 Benjamin A. MacFarlane,2 Jeong-Eun Lee,1 Dimitris Stamatellos,2 Gregory Herczeg,3Doug Johnstone,4, 5 Carlos Contreras Peña,6 Watson Varricatt,7 Klaus W. Hodapp,7 Huei-Ru Vivien Chen,8and Sung-Ju Kang9
1 School of Space Research and Institute of Natural Sciences, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si,

サブミリ(850μm)波で強度変動が見られた原始星をモデリングした
Gyeonggi-do 446-701, Korea; jeongeun.lee@khu.ac.kr, giseon@khu.ac.kr

2 Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy, University of Central Lancashire, Preston, PR1 2HE, UK

3 Kavli Instituteburst
・Accretion(episodic
accretion)=>University,
Luminosity
for Astronomy
and Astrophysics,
PekingYiheyuanproblemの解決策
5, Haidian Qu, 100871 Beijing, China
4 NRC Herzberg Astronomy and Astrophysics, 5071 West Saanich Rd, Victoria, BC, V9E 2E7, Canada
・EC 35 はサーペンスメインにあるClass
I 原始星
5 Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8P 1A1, Canada
6 School of Physics,
JCMTのtransient
サーベイで850μmで数ヶ月で1.5倍ほどの増光が見られる
Astrophysics Group, University of Exeter, Stocker
Road, Exeter EX4 4QL, UK
7 Institute for Astronomy, University of Hawaii, 640 N. Aóhoku Place, Hilo, HI 96720, USA*K-bandでは543日の周期
8 Department of Physics and Institute of Astronomy, National Tsing Hua University, Taiwan
・EC53の2D/3Dの輻射輸送モデリングを行なった(quiescentphases)。
9 Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon and34055,outburst
Republic of Korea(Received -; Revisedモデルの変数-; Accepted -)・radial proﬁle,エンベロープの大きさ
In the episodic accretion scenario, a large fraction of the protostellar mass accretes during repeatedのオープニングアングル
and large bursts of accretion. Since outbursts on cavity
protostars
are typically identified at specific
ABSTRACTwavelengths, interpreting these outbursts requires converting this change in flux to a change in totalluminosity. The Class I young stellar object EC 53 in the Serpens Main cloud has undergone repeated=>赤のモデルが一番合いそう
increases in brightness at 850 µm that are likely caused by bursts of accretion. In this study, we
perform two- and three-dimensional continuum radiative transfer modeling to quantify the internal
luminosity ◇が観測点
rise in EC 53 that corresponds to theInclinaTon
factor of ⇠1.5はface-on(30deg)に近い
enhancement in flux at 850 µm.
We model the spectral energy distribution and radial intensity profile in both the quiescent andoutburst phases. The internal luminosity in the ・3Dmodel
outburst phaseはdiskのmidplaneis ⇠ 3.3 times brighterがより高than theluminosity in the quiescent phase. The radial intensity
profile analysis demonstrates that the detected
密度なので、短波長側で合わない
sub-mm flux variation of EC 53 comes from the heated envelope by the accretion burst. We also findthat the role of external heating of the EC 53 envelope by the interstellar radiation field is insignificant.

2の続きOutburst phase とQuiescent phaseのSEDサブミリ(850μm)fluxが1.5倍になるように合わせたが、短波長側の方もよくあっている
L_int が3.3倍になっている G. Baek et al.
1.0

Quiescent phase

0.5

2

2

log10 I(b) [mJy/arcsec ]1.0

log10 I(b) [mJy/arcsec ]

12

0.0

-0.5

-1.0
2.5

Envelope direction
Outflow direction
Model: L* = 6Lô

3.0

3.5
log10 (bb) [AU]

4.0

4.5

◻が観測点

Outburst phase

0.5

0.0

-0.5

-1.0
2.5

Envelope direction
Outflow direction
Model: L* = 20Lô

3.0

3.5
log10 (bb) [AU]

4.0

4.5

850μmのradialintensity profile
Figure 12. The 850 µm radial intensity profiles of EC 53 for quiescent (left) and outbursting (right) phases. Purple and orange
solid lines present
the radial intensity profilesprofile
along the の方がより増光していることから、
envelope (P.A.= 90 ) and outflow cavity (P.A.= 330 ) directions,outflowに垂直な軸のradialrespectively. The dashed line is the modeled radial intensity profiles (2D) without ISRF from our fiducial model.
増光は中心星の増光ということで良さそう(IRSFの影響も多少あり)
cial 2D models for a given cavity opening angle (seequiescent (left) and outbursting (right) phases. Only

nature of the methanol maser ring G23.657−00.127. II. Expansion of the maser
3 The
structure
Anna Bartkiewicz1 , Alberto Sanna2,3 , Marian Szymczak1 , Luca Moscadelli4, Huib Jan van Langevelde5,6
and Pawel Wolak1
Institute of Astronomy, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka
5, 87-100 Torun, Poland; 2 INAF, Istituto di Radioastronomia & Italian ALMA Regional Centre, Via P. Gobetti 101,
40129, Bologna, Italy; 3 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121, Bonn, Germany; 4 INAF,
Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy; 5 Joint Institute for VLBI ERIC (JIVE),
Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, The Netherlands; 6 Sterrewacht Leiden, Leiden University, Postbus
9513, 2300 RA Leiden, The Netherlands
1E-mail contact: annan at astro.umk.pl
Ring-like distributions of the 6.7 GHz methanol maser spots at milliarcsecond scales represent a family of molecular structures of unknown origin associated with high-mass young stellar objects (HMYSOs). We aim to study
G23.657−00.127, which has a nearly circular ring of the 6.7 GHz methanol masers, and is the most suitable target totest hypotheses on the origin of the maser rings. The European Very Long Baseline Interferometry Network (EVN)
was used at three epochs spanning 10.3 yr to derive the spatio-kinematical structure of the 6.7 GHz methanol maser
emission in the target. The maser cloudlets, lying in a nearly symmetric ring, expand mainly in the radial direction
with a mean velocity of 3.2 km s−1 . There is an indication that the radial component of the velocity increases withcloudlet’s distance from the ring centre. The tangential component does not show any clear evidence for rotation of thecloudlets or any relationship with distance from the ring centre. The blue-shifted masers may hint at an anticlockwise
rotation of cloudlets in the southern part of the ring. The nearly circular structure of the ring clearly persisted formore than 10 yr. Interferometric data demonstrated that about one quarter of cloudlets show significant variability
in their brightness, although the overall spectrum was non-variable in single-dish studies. Taking into account thethree-dimensional motion of the maser cloudlets and their spatial distribution along a small ring, we speculate about
two possible scenarios where the methanol masers trace either a spherical outflow arising from an (almost) edge-on
disc, or a wide angle wind at the base of a protostellar jet. The latter is associated with near- and mid-infraredemission detected towards the ring. High angular resolution images of complementary (thermal) tracers are needed tointerpret the environment of methanol masers.

大質量原始星の周りにはリング状のメタノールメーザースポットがある
http://arxiv.org/pdf/2004.00916
これが膨張していることがわかった。
Dynamical cloud formation traced byatomic andmolecular gas- Edge-on
diskからのOu^lowor 広角のjetか？
Accepted by Astronomy and Astrophysics

1

1

1

1

1

2

2

3

4 Dynamical cloud formation traced by atomic and molecular gas
H. Beuther1 , Y. Wang1 , J. Soler1 , H. Linz1 , J. Henshaw1 , E. Vazquez-Semadeni2 , G. Gomez2 , S. Ragan3 , Th. Henning1 ,S.C.O. Glover4 , M.-Y. Lee5 , and R. Güsten6◻枠が新しい観測の範囲

1

Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany, e-mail: name@mpia.de
Instituto de Radioastronomı́a y Astrofı́sica, Universidad Nacional Autonoma de Mexico, Morelia, Michoacan 58089, Mexico
3
School of Physics and Astronomy, Cardiﬀ University, Queen’s Buildings, The Parade, Cardiﬀ CF24 3AA, UK
4
University of Heidelberg, Institute for Theoretical Astrophysics, Albert-Ueberle-Str. 2, 69120 Heidelberg, Germany
5
Korea Astronomy and Space Science Institute, 776 Daedeok-daero, 34055 Daejeon, Republic of Korea
6
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany

大質量星形成現場(IRDC)における原子ガスと分子ガスを電波望遠鏡観測し、運動状態を調べた
2

Version of April 14, 2020
ABSTRACT
モチベーション：原子/分子雲形成に迫りたい。
ターゲット分子雲:
G28.3
銀河面にあるIRDC
Context. Atomic and molecular
cloudformation is a dynamical process. However, kinematic signatures of these processes are stillobservationally poorly
constrained.
カラー: 8μm
新しい観測:APEX
による [CI]と13CO (3-2)
Aims. Identify and characterize the cloud formation signatures in atomic and molecular gas.
Methods. Targeting the cloud-scale
environment
cloud G28.3, we
employ spectralline imaging
875μm(ATLASGAL)
アーカイブデータ:
HI, 13CO(1-0) of the prototypical infrared darkコントア:
13

observations of the two atomic lines HI and [CI] as well as molecular lines observations in CO in the 1–0 and 3–2 transitions.
The analysis comprises investigations of the kinematic properties of the diﬀerent tracers, estimates of the mass flow rates, velocity
structure functions, a Histogram of Oriented Gradients (HOG) study as well as comparisons to simulations.
Results. The central IRDC is embedded in a more diﬀuse envelope of cold neutral medium (CNM) traced by HI self-absorption(HISA) and molecular gas. The spectral line data as well as the HOG and structure function analysis indicate a possible kinematic
decoupling of the HI from the other gas compounds. Spectral analysis and position-velocity diagrams reveal two velocity componentsthat converge at the position of the IRDC. Estimated mass flow rates appear rather constant from the cloud edge toward the center.
The velocity structure function analysis is consistent with gas flows being dominated by the formation of hierarchical structures.
Conclusions. The observations and analysis are consistent with a picture where the IRDC G28 is formed at the center of two converging gas flows. While the approximately constant mass flow rates are consistent with a self-similar, gravitationally driven collapseof the cloud, external compression by, e.g., spiral arm shocks or supernovae explosions cannot be excluded yet. Future investigations
should aim at diﬀerentiating the origin of such converging gas flows.

HISA (HI Self-absorption)

Key words. ISM: clouds – ISM: kinematics and dynamic – ISM: structure – ISM: general – ISM: evolution – Stars: formation

1. Introduction
HIと13CO(1-0)のスペクトル

one side, and cloud collapse on the other side is that in the con13CO (1-0)
CMNをトレース
verging gas flow and cloud-cloud collision picture the compres-4の続き [CI]

13CO
(3-2)

HISAの速度マップ
13COの速度マップ
1. HI self-absorpTon (HISA)でトレースされるC cold neutral medium (CNM)
はCIやCOのラインの速度とはdecoupe している

4の続き

13COから求めた柱密度と南北の速度の差
2. IRDCに向かって２つの速度構造 (2つの一定のmass flowか?)
consistent with a self-similar, gravitationally driven collapse of the cloud, external
compression by, e.g., spiral arm shocks or supernovae explosions cannot be excluded yet.

of convective low-mass to high-mass second Larson cores
5 BirthAsmita Bhandare , Rolf Kuiper , Thomas Henning , Christian Fendt , Mario Flock , and Gabriel1

2,1

1

1

1

Dominique Marleau

2,3,1

Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany; 2 Institut für Astronomie undAstrophysik, Universität Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen, Germany; 3 Physikalisches Institut,
Universität Bern, Gesellschaftsstr. 6, CH-3012 Bern, Switzerland

1

E-mail contact: bhandare at mpia.de
Stars form as an end product of the gravitational collapse of cold, dense gas in magnetized molecular clouds. This
multi-scale scenario occurs via the formation of two quasi-hydrostatic cores and involves complex physical processes,
which require a robust, self-consistent numerical treatment. The aim of this study is to understand the formationand evolution of the second Larson core and the dependence of its properties on the initial cloud core mass. We
used the PLUTO code to perform high resolution, 1D and 2D RHD collapse simulations. We include self-gravity
and use a grey FLD approximation for the radiative transfer. Additionally, we use for the gas EOS density- andtemperature-dependent thermodynamic quantities to account for the eﬀects such as dissociation, ionisation, andmolecular vibrations and rotations. Properties of the second core are investigated using 1D studies spanning a wide
range of initial cloud core masses from 0.5 to 100 M⊙ . Furthermore, we expand to 2D collapse simulations for a few
cases of 1, 5, 10, and 20 M⊙ . We follow the evolution of the second core for ≥ 100 years after its formation, for eachof these non-rotating cases. Our results indicate a dependence of several second core properties on the initial cloudcore mass. For the first time, due to an unprecedented resolution, our 2D non-rotating collapse studies indicate thatconvection is generated in the outer layers of the second core, which is formed due to the gravitational collapse of a
1 M⊙ cloud core. Additionally, we find large-scale oscillations of the second accretion shock front triggered by thestanding accretion shock instability, which has not been seen before in early evolutionary stages of stars. We predictthat the physics within the second core would not be significantly influenced by the eﬀects of magnetic fields or an
initial cloud rotation.
Accepted by A&A
http://arxiv.org/pdf/2004.12419

セカンドコアの進化が初期のコアの質量でどのように変わるか？
1Dで0.5 ~ 100Mo
2Dで1, 5, 10, 20 Mo
セカンドコアの形成から100年以上計算(回転なし)
12
対流がセカンドコアの外側で生み出されていた

6

GW Ori: Interactions Between a Triple-star System and its Circumtriple Disk in Action

Jiaqing Bi,1 Nienke van der Marel,1, 2 Ruobing Dong,1 Takayuki Muto,3 Rebecca G. Martin,4Jeremy L. Smallwood,4 Jun Hashimoto,5 Hauyu Baobab Liu,6 Hideko Nomura,7, 8 Yasuhiro Hasegawa,9Michihiro Takami,6 Mihoko Konishi,10 Munetake Momose,11 Kazuhiro D. Kanagawa,12 Akimasa Kataoka,7Tomohiro Ono,13, 14 Michael L. Sitko,15, 16 Sanemichi Z. Takahashi,7, 17 Kengo Tomida,14, 18 andTakashi Tsukagoshi7
1 Department of Physics & Astronomy, University of Victoria, Victoria, BC V8P 5C2, Canada

GW Oriという階層連星 A-(1AU)-B-(8AU)-C という感じ
CanadaのALMAを用いた1.3mmと12COの観測
3 Division of Liberal Arts, Kogakuin University, 1-24-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo 163-8677, Japan
46, 188,
388 AUの場所にリング構造 (外側のリングはこれまででもっとも大きい)
4 Departmentof Physics & Astronomy, University of Nevada, Las Vegas, 4505 South Maryland Parkway, Las Vegas, NV 89154, USA
5 Astrobiology Center, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
質量(dustmass)は74, 168, and 245 Earth masses
6 Academia Sinica Institute of Astronomy & Astrophysics, No. 1, Sec. 4, Roosevelt Rd, Taipei 10617, Taiwan
ダストのリングはミスアラインしている(COの観測からもわかる)
7 Division of Science, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
8 Department
これらは円盤と3重星のdynamicalinteractionによって形成されたof Earth & Planetary Sciences, Tokyo Instituteof Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8551, Japan

2 Herzberg Astronomy & Astrophysics Programs, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC V9E 2E7,

9 Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
10 Faculty of Science & Technology, Oita University, 700 Dannoharu, Oita 870-1192, Japan
11 College of Science, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan
12 Research Center for the Early Universe, Graduate School of Science, University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
13 Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
14 Department of Earth & Space Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
15 Department of Physics, University of Cincinnati, Cincinnati, OH 45221, USA
16 Space Science Institute, 475 Walnut Street, Suite 205, Boulder, CO 80301, USA
17 Department of Applied Physics, Kogakuin University, 1-24-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo 163-8677, Japan
18 Astronomical Institute, Tohoku University, Sendai, Miyagi 980-8578, Japan

ABSTRACTGW Ori is a hierarchical triple system with a rare circumtriple disk. We present Atacama Large
Millimeter/submillimeter Array (ALMA) observations of 1.3 mm dust continuum and 12 CO J = 2 1
molecular gas emission of the disk. For the first time, we identify three dust rings in the GW Ori disk
at ⇠ 46, 188, and 338 AU, with estimated dust mass of 74, 168, and 245 Earth masses, respectively. To
our knowledge, its outermost ring is the largest dust ring ever found in protoplanetary disks. We use

6の続き

7 Kinematics of T Tauri Stars Close to the Sun from the Gaia DR2 Catalogue
V.V. Bobylev1
1

Pulkovo Astronomical Observatory, Russian Academy of Sciences, Pulkovskoe sh. 65, St. Petersburg, 196140 Russia

E-mail contact: vbobylev at gaoran.ru
The spatial and kinematic properties of a large sample of young T Tauri stars from the solar neighborhood 500 pc
in radius have been studied. The following parameters of the position ellipsoid have been determined from the mostprobable members of the Gould Belt: its sizes are 350 × 270 × 87 pc and it is oriented at an angle of 14◦ ±1◦ to the
Galactic plane with a longitude of the ascending node of 297◦±1◦ . An analysis of the motions of stars from this sample
has shown that the residual velocity ellipsoid with principal semiaxes σ1,2,3 = (8.87, 5.58, 3.03)±(0.10, 0.20, 0.04) km s−1
is oriented at an angle of 22◦ ±1◦ to the Galactic plane with a longitude of the ascending node of 298◦±2◦ . It has been
established that much of the expansion eﬀect (kinematic K eﬀect) typical for Gould Belt stars, 5–6 km s−1 kpc−1 , canbe explained by the influence of a Galactic spiral density wave with a radial perturbation amplitude fR ∼ 5 km s−1 .
Accepted by Astronomy Letters
http://arxiv.org/pdf/2004.07291

太陽系近傍500 pcにある T Tauri星の固有運動カタログ
13
Gould Belt のメンバーのパラメーターを決めた
銀河のスパイラル密度波の影響によって説明される