星形成ゼミ
The Star Formation Newsletter 331
57~63

徳田一起 (大阪府立大学/NAOJ)

57

Testing viscous disc theory using the balance between stellar accretion andexternal photoevaporation of protoplanetary discs

58

Rotation of Two Micron All Sky Survey Clumps in Molecular Clouds

59

Super-resolution Imaging of the Protoplanetary Disk HD 142527 Using Sparse
Modeling

60

Distances and statistics of local molecular clouds in the first Galactic quadrant

61

Resolution-dependent Subsonic Non-thermal Line Dispersion Revealed by ALMA

62

Filament Intersections and Cold Dense Cores in Orion A North

63

The Ophiuchus DIsc Survey Employing ALMA (ODISEA). II. The effect of stellar
multiplicity on disc properties

57
Testing viscous disc theory using the balance between stellar accretion and external
photoevaporation of protoplanetary discs
Andrew J. Winter1,2 , Megan Ansdell3,4 , Thomas J. Haworth5 , and J.M. Diederik Kruijssen1
Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, 69120
Heidelberg, Germany; 2 School of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, UK; 3 Flatiron
Institute, Simons Foundation, 162 Fifth Ave, New York, NY 10010, USA; 4 NASA Headquarters, 300 E Street SW,
Washington, DC 20546, USA; 5 Astronomy Unit, School of Physics and Astronomy, Queen Mary University of London,
Mile End Road, London, United Kingdom
1E-mail contact: andrew.winter at uni-heidelberg.de
The nature and rate of (viscous) angular momentum transport in protoplanetary discs (PPDs) has important consequences for the formation process of planetary systems. While accretion rates onto the central star yield constraints
on such transport in the inner regions of a PPD, empirical constraints on viscous spreading in the outer regions remainchallenging to obtain. Here we demonstrate a novel method to probe the angular momentum transport at the outeredge of the disc. This method applies to PPDs that have lost a significant fraction of their mass due to thermal
winds driven by UV irradiation from a neighbouring OB star. We demonstrate that this external photoevaporation
can explain the observed depletion of discs in the 3–5 Myr old σ Orionis region, and use our model to make predictions motivating future empirical investigations of disc winds. For populations of intermediate-age PPDs, in viscousmodels we show that the mass flux outwards due to angular momentum redistribution is balanced by the mass-loss
in the photoevaporative wind. A comparison between wind mass-loss and stellar accretion rates therefore offers an
independent constraint on viscous models in the outer regions of PPDs.
Accepted by MNRAS Letters
http://arxiv.org/pdf/2006.04819

Rotation of Two Micron All Sky Survey Clumps in Molecular Clouds
Xuefang Xu1,2 , Di Li1,2,3 , Y.Sophia Dai4 , Paul F. Goldsmith5 and Gary A. Fuller6
CAS Key Laboratory of FAST, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101,
China; 2 University of Chinese Academy of Sciences, Beijing 100049, China; 3 NAOC-UKZN Computational Astrophysics Centre, University of KwaZulu-Natal, Durban 4000, South Africa; 4 Chinese Academy of Sciences South1

http://arxiv.org/pdf/2006.04819
58

Rotation of Two Micron All Sky Survey Clumps in Molecular Clouds
Xuefang Xu1,2 , Di Li1,2,3 , Y.Sophia Dai4 , Paul F. Goldsmith5 and Gary A. Fuller6
CAS Key Laboratory of FAST, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101,
China; 2 University of Chinese Academy of Sciences, Beijing 100049, China; 3 NAOC-UKZN Computational Astrophysics Centre, University of KwaZulu-Natal, Durban 4000, South Africa; 4 Chinese Academy of Sciences SouthAmerica Center for Astronomy (CASSACA), NAOC, Beijing 100101, China; 5 Jet Propulsion Laboratory, California
Institute of Technology, Pasadena, CA 91109, USA; 6 Jodrell Bank Centre for Astrophysics, Department of Physics
and Astronomy, the University of Manchester, Oxford Road, Manchester, M13 9PL, UK
1

E-mail contact: xfxu at nao.cas.cn
We have analyzed the rotational properties of 12 clumps using 13 CO (1–0) and C18 O (1–0) maps of the Five College
Radio Astronomy Observatory 13.7 m radio telescope. The clumps, located within molecular clouds, have radii (R)in the range of 0.06 – 0.27 pc. The direction of clump elongation is not correlated with the direction of the velocity
gradient. We measured the specific angular momentum (J/M) to be between 0.0022 and 0.025 pc km s−1 based on 13 CO
images, and between 0.0025 and 0.021 pc km s−1 based on C18 O images. The consistency of J/M based on different
tracers indicates the 13 CO and C18 O in dense clumps trace essentially the same material despite significantly different
opacities. We also found that J/M increases monotonically as a function of R in power–law form, J/M ∝ R1.58 ± 0.11 .
The ratio between rotation energy and gravitational energy, β, ranges from 0.0012 to 0.018. The small values of β
imply that rotation alone is not sufficient to support the clump against gravitational collapse.
Accepted by Astrophysical Journal
https://arxiv.org/pdf/2006.04309

13.7m電波望遠鏡
Super-resolution ImagingFCRAO
of the Protoplanetary
Disk HD 142527 Using Sparse Modeling

Masayuki Yamaguchi1,2 , Kazunori
Akiyama2,3,4,5 , Takashi Tsukagoshi2 , Takayuki Muto6 , Akimasa Kataoka2,7
土橋さんの源光カタログのクランプ
et al.
1

13COやC18Oで回転を測定

Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo
34

113-0033, Japan; 2 National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; 3
National Radio Astronomy Observatory, 520 Edgemont Rd, Charlottesville, VA 22903, USA; 4 Massachusetts Instituteof Technology, Haystack Observatory, 99 Millstone Rd, Westford, MA 01886, USA; 5 Black Hole Initiative, Harvard
University, 20 Garden Street, Cambridge, MA 02138, USA; 6 Division of Liberal Arts, Kogakuin University, 1-242 Nishi-Shinjuku, Shinjuku-ku, Tokyo 163-8677, Japan; 7 Department of Astronomical Science, School of PhysicalSciences, Graduate University for Advanced Studies, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
E-mail contact: masayuki.yamaguchi.astro at gmail.com
With an emphasis on improving the fidelity even in super-resolution regimes, new imaging techniques have been
intensively developed over the last several years, which may provide substantial improvements to the interferometricobservation of protoplanetary disks. In this study, sparse modeling (SpM) is applied for the first time to observational
data sets taken by the Atacama Large Millimeter/submillimeter Array (ALMA). The two data sets used in this study
were taken independently using different array configurations at Band 7 (330 GHz), targeting the protoplanetary disk
around HD 142527; one in the shorter-baseline array configuration (∼430 m), and the other in the longer-baselinearray configuration (∼1570 m). The image resolutions reconstructed from the two data sets are different by a factorof ∼3. We confirm that the previously known disk structures appear on the images produced by both SpM and
CLEAN at the standard beam size. The image reconstructed from the shorter-baseline data using the SpM matches
that obtained with the longer-baseline data using CLEAN, achieving a super-resolution image from which a structure
finer than the beam size can be reproduced. Our results demonstrate that on-going intensive development in the SpM
imaging technique is beneficial to imaging with ALMA.
Accepted by ApJ

スパースモデリングによる高解像度化
ベースラインが3倍以上のデータをDistances and statistics of local molecular
clouds in the first Galactic quadrant
再現できることを確認した。
1
1
1
1
1
http://arxiv.org/pdf/2004.10989

Qing-Zeng Yan , Ji Yang , Yang Su , Yan Sun and Chen Wang

Purple Mountain Observatory and Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, Nanjing
210034, People’s Republic of China
1E-mail contact: jiyang at pmo.ac.cn

60 Distances and statistics of local molecular clouds in the first Galactic quadrant
Qing-Zeng Yan1 , Ji Yang1 , Yang Su1 , Yan Sun1 and Chen Wang1

Purple Mountain Observatory and Key Laboratory of Radio Astronomy, Chinese Academy of Sciences,
中国の紫金山天文台によるMilky Way Imaging Scroll Painting (MWISP) CO survey の解析
210034, People’s Republic of China
第一象限(25.8°<
l <at49.7°,
E-mail contact:jiyangpmo.ac.cn|b|<5°)で15 kpc以内(-6 < V_LSR < 30 km/s)
1

We present an analysis of local molecular clouds (−6 < VLSR < 30 km s−1・クラスタリング解析, i.e., <1.5 kpc) in the first Galactic◦◦◦(25. 8 < l < 49. 7 and |b| < 5 ), a pilot region of the Milky Way Imaging Scroll Painting (MWISP) CO surve(SCIMES)でそこそこ大き
the SCIMES algorithm to divide large molecular clouds into moderate-sized
ones, we determined distancmolecular clouds with the background-eliminated extinction-parallax (BEEP)
method using the Gaia DR2
いクラウドを28個同定
measurements aided by AG and AV , and the distance ranges from 250 pc to about 1.5 kpc. These incomplete
samples indicate a linear relationship between the distance and the radial velocity (VLSR ) with a scatter ofand kinematic distances may be systematically larger for local molecular・BEEP*1という手法で距
clouds. In order to investigate funproperties of molecular clouds, such as the total sample number, the 離同定
linewidth, the brightness tempera
physical area, and the mass, we decompose the spectral cube using the DBSCAN algorithm. Post selection cr
imposed on DBSCAN clusters to remove the noise contamination, and we found that the separation of molecu
individuals is reliable based on a definition of independent consecutive ・力学的距離は系統的にstructures in l-b-V space. The comof the local molecular cloud flux collected by the MWISP CO survey is about 80%. The physical area, A,
大きくなってしまう
power-law distribution, dN/dA ∝ A−2.20±0.18 , while the molecular cloud mass also follows a power-law dis
but slightly flatter, dN/dM ∝ M −1.96±0.11 .

・DBSCAN*2アルゴリズム
でクラウドを分ける
http://arxiv.org/pdf/2006.13654
COの積分強度とLV図-面積関数は-2.2のベキ*1 theResolution-dependent
background-eliminated extinction-parallax(BEEP) method
Subsonic Non-thermalLine Dispersion
Revealed by ALM-質量関数は-1.96のベキ
using Nannan
the GaiaYue
DR21 ,parallax
by1A, GJonathan
and AV Henshaw3 , Diego Mardones4 and Z
Di Li1 , measurements
Qizhou Zhang2 ,aided
Lei Zhu
特に物理的な理由は議*2 density-based
spatial clustering of applications with noise
Ren1
論していなかった1
2
Accepted by ApJ

National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012; Harvard-Smithsonia
for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA; 3 Max-Planck-Institut für Astronomie, K

60の続き Generally, we have three types of molecular cloud samples:(1) 距離の見積もりはSCIMES (一番大きい構造の中途半端なsubstructure)(2) samples with small molecular clouds produced with SCIMES;(3) samples produced with DBSCAN. 統計はこっち, (2)は比較用

近い方の力学的距離
dash(l=25°)
dotted(l=50°)

Fitting 結果

Face-on view
This systematic shift indicates that the motion of local molecular clouds (> 1 kpc) may notprecisely follow the Galactic rotational curve.

61 Resolution-dependent Subsonic Non-thermal Line Dispersion Revealed by ALMA

Nannan Yue1 , Di Li1 , Qizhou Zhang2 , Lei Zhu1 , Jonathan Henshaw3 , Diego Mardones4 and Zhiyuan
Ren1

National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012; 2 Harvard-Smithsonian Center
for Astrophysics, 60 Garden 4Street, Cambridge, MA 02138, USA; 3 Max-Planck-Institut für Astronomie, Königstuhl
1

17, D-69117 Heidelberg, Germany;

Departameto de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile

E-mail contact: nnyue at nao.cas.cn

35

We report here Atacama Large Millimeter/submillimeter Array (ALMA) N2 H+ (1-0) images of the Orion Molecular
Cloud 2 and 3 (OMC-2/3) with high angular resolution (3” or 1200 au) and high spatial dynamic range. Combining
dataset from the ALMA main array, ALMA Compact Array (ACA), the Nobeyama 45m Telescope, and the JVLA
(providing temperature measurement on matching scales), we find that most of the dense gas in OMC-2/3 is subsonic(σNT /cs = 0.62) with a mean line width (∆υ) of 0.39 km s−1 FWHM. This is markedly different from the majorityof previous observations of massive star-forming regions. In contrast, line widths from the Nobeyama Telescope aretransonic at 0.69 km s−1 (σNT /cs = 1.08). We demonstrated that the larger line widths obtained by the single-dishtelescope arose from unresolved sub-structures within their respective beams. The dispersions from larger scales σls2222(as traced by the Nobeyama Telescope) can be decomposed into three components σls
= σss
+ σbm
+ σrd
, wheresmall-scale σss is the line dispersion of each ALMA beam, bulk motion σbm is dispersion between peak velocity of each
ALMA beam, and σrd is the residual dispersion. Such decomposition, though purely empirical, appears to be robust
throughout our data cubes. Apparent supersonic line widths, commonly found in massive molecular clouds, are thus
likely due to the effect of poor spatial resolution. The observed non-thermal line dispersion (sometimes referred toas ’turbulence’) transits from supersonic to subsonic at ∼ 0.05 pc scales in OMC-2/3 region. Such transition could
be commonly found with sufficient spatial (not just angular) resolution, even in regions with massive young clusters,such as Orion molecular clouds studied here.
Accepted by Research in Astronomy and Astrophysics

ALMAによるオリオン領域(OMC-2/3)のN2H+ (1-0)輝線の観測
Filament Intersections and Cold Dense Cores in Orion A North
高分解能でみたら線幅はsubsonicだった
Chao Zhang1 , Zhiyuan Ren1 , Jingwen Wu1 , Di Li1,2,3 , Lei Zhu7 et al.
http://arxiv.org/pdf/2006.04168

National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing
100101, China; 2 University of Chinese Academy of Sciences, Beijing 100049, China; 3 NAOC-UKZN Computational
Astrophysics Centre (NUCAC), University of KwaZulu-parental, Durban 4000, South Africa; 4 Chinese Academy of
Sciences South America Center for Astronomy

1E-mail contact: renzy at nao.cas.cn
We studied the filament structures and dense cores in OMC-2,3 region in Orion A North molecular cloud using the62

Filament Intersections and Cold Dense Cores in Orion A North
Chao Zhang1 , Zhiyuan Ren1 , Jingwen Wu1 , Di Li1,2,3 , Lei Zhu7 et al.

National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District
100101, China; 2 University of ALMA(7m+12m)によるOrionA分子雲
Chinese Academy of Sciences, Beijing 100049, China; 3 (OMC-2/3)
NAOC-UKZN Comp
Astrophysics Centre (NUCAC), University of KwaZulu-parental, Durban 4000, South Africa; 4 Chinese Ac
Sciences South America CenterによるN2H+(1-0)輝線の観測
for Astronomy

1E-mail contact: renzy at nao.cas.cn

We studied the filament structures and dense cores in OMC-2,3 region in Orion A North molecular cloud
high-resolution N2 H+ (1–0) spectral cube observed with the Atacama Large Millimeter/Submillimeter Array (The filament network over a total length of 2 pc is found to contain 170 intersections and 128 candidate den
The dense cores are all displaced from the infrared point sources (possible young stars), and the major fractio(103) are located around the intersections. Towards the intersections, there is also an increasing trend forcolumn density Ntot as well as the the power-law index of the column-density Probability Distribution FunPDF), suggesting that the intersections would in general have more significant gas assembly than the other pfilament paths. The virial analysis shows that the dense cores mostly have virial mass ratio of αvir = Mvir /Msuggesting them to be bounded by the self gravity. In the mean time, only about 23 percent of the cores hav
mass ratio of αcrit = Mcrit /Mgas < 1.0, suggesting them to be unstable against core collapse. Combining thesit shows that the major fraction of the cold starless and possible prestellar cores in OMC-2,3 are being aaround the intersections, and currently in a gravitationally bound state. But more extensive core collapse
formation may still require continuous core-mass growth or other perturbation.
Accepted by MNRAS
http://arxiv.org/pdf/2006.13410

The Ophiuchus DIsc Survey Employing ALMA (ODISEA). II. The effect ofmultiplicity on disc properties

Alice Zurlo1,2 , Lucas A. Cieza1 , Sebastián Pérez3 , Valentin Christiaens4 , Jonathan P. Williams

Núcleo de Astronomía, Facultad de Ingeniería, Universidad Diego Portales, Av. Ejercito 441, Santiago,
Escuela de Ingeniería Industrial, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejer

1

カラー: ALMA N2H+ (1-0) ~3"分解能
コントア: JCMT
870μm連続波 ~15"36

62の続き結論まとめ
1. 170個ほどfilament が交差している場所を見つけた
線幅(ΔV)は0.6km/s以下で結構細くて単一成分 (複数成分がマージしている?)
2. 128個ほどコアを見つけた。そのうち103個ほどはフィラメントの交点
・σ_v = 0.03-0.24 km/s
・質量は0.07-1.9 Mo
3. N-PDFはフィラメントの交点でpower-low tale になる傾向
4. ビリアルパラメータα_vir はほとんど1以下
In general, the cold prestellar cores in OMC-2,3 may require further mass growthor other perturbations to more broadly initiate their star formation.
(質量関数は導出していなかった)

Ophiuchus DIsc Survey Employing ALMA (ODISEA). II. The effect of stellar
63 Themultiplicity on disc properties
Alice Zurlo1,2 , Lucas A. Cieza1 , Sebastián Pérez3 , Valentin Christiaens4 , Jonathan P. Williams5 et al.
Núcleo de Astronomía, Facultad de Ingeniería, Universidad Diego Portales, Av. Ejercito 441, Santiago, Chile;
We present
Adaptive Optics (AO) near infrared
Escuela de Ingeniería Industrial, Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Av. Ejercito 441,
(NIR) observations using VLT/NACO andKeck/NIRC2 of ODISEA targets. (seeing 0."3-0."4)36
ODISEA: Ophiuchus分子雲のALMA discサーベイ
1

2

The NIR-ODISEA survey 147天体-20/21天体でbinary であることを再確認-20の連星, 1つの三重星を真検出
セカンダリーの質量はsub-stellar (30-50Mjup)
連星系のdiscダスト質量は最大で~50 M ⊕単独星は~200 M⊕
10 M⊕ を超える質量はseparationが100 au以上のbinaryでのみ見られたDiscの最大サイズもbinaryよりsingleの方がでかい
Ophiuchusの場合はそもそも質量/サイズが小さいので、(例えばTaurusはもう少し大きい)(visual) binary の効果でこのようになったかど
うかよくわからない

VLT/NACO and Keck/NIRC2

コントアはALMA 1.3mm
ビームサイズ(0. 98×0."74)

63の続きカテゴリー

個数Single objects

赤外超過なし (60) and NIR-ODISEA (193)

252

Res

複数のdisc (ALMAで検出できて2つ以上に分解できてる)

11UR連星であるがALMAで分解できていない

3

ND of component(s)連星でどっちがもしくは両方がALMAで検出できていない

25

No IR excess binary連星で赤外超過がない (ALMAではターゲットにしていない)

26

図7
Singleの方が重いdisc質量

図12
discサイズの積算
ヒストグラム図13
separation 100auより大きいdiscが10M ⊕を超える