STAR FORMATION NEWSLETTER#302 36 - 45
樋⼝公紀 (九州⼤学)

Paper lists
36. Evidence for feedback and stellar-dynamically regulated bursty star cluster formation:
the case of the Orion Nebula Cluster
37. Episodic accretion: the interplay of infall and disc instabilities
38. ALMA Dust Polarization Observations of Two Young Edge-on Protostellar Disks
39. Bayesian assessment of moving group membership: importance of models and priorknowledge
40. Molecular Gas Toward the Gemini OB1 Molecular Cloud Complex II: CO Outflow
Candidates with Possible WISE Associations
41. Filamentary Fragmentation and Accretion in High-Mass Star-Forming MolecularClouds
42. Molecular reconnaissance of the β Pictoris gas disk with the SMA: a low
HCN/(CO+CO2) outgassing ratio and predictions for future surveys
43. An optical parsec-scale jet from a massive young star in the Large Magellanic Cloud
44. Molecular Gas in Debris Disks around Young A-type Stars
45. Candidate Water Vapor Lines to Locate the H2O Snowline Through High-dispersion
Spectroscopic Observations. III. Sub-millimeter H216O and H218O Lines36. Evidence for feedback and stellar-dynamically regulated bursty
star cluster formation: the case of the Orion Nebula Cluster
Kroupa et al. Accepted by A&A
⼩さい星団が前段階で作られ、それがmergeするのでは時間が⾜りない。
-> the repeated stellar-dynamicaltermination of feedback-halted
filament-accretion model

http://arxiv.org/pdf/1801.03095.pdf

Orion Nebula Cluster (ONC)- about 400 pc distant from the Sun- 1-3 Myr old- the nearest massive young stellar cluster- contain three well separated sequences.
2.87 Myr

1.88 Myr

1.24 Myr

このモデルで、VYC内でmultiple co-eval populationsを⽣成する、この妥当性を検証

Beccari et al. (2017)

the repeated stellar-dynamical terminationof feedback-halted filament-accretion model結論
molecular cloud coresからのprotoclusterへのmolecular gasのinflow ratesが1000 - 6000 Msun /Myr の範囲内であれ
ば、1Myr内に300 - 2000 Msunの質量範
囲のfirst co-eval population of starsを作ることができ、なおかつO starは互いに相互作⽤をして、外部に放出されることが可能。
-> イオン化源がなくなれば、 co-evalpopulation of starsの形成が再開される。

38. ALMA Dust Polarization Observations of Two Young Edge-on
Protostellar Disks
Chin-Fei Lee et al.

Accepted by ApJ

https://arxiv.org/pdf/1801.03802

Polarized emission is detected in two young nearly edge-on protostellar
disks in 343 GHz continuum at ∼ 50 au (∼ 0”. 12) resolution with ALMA.
Observation- HH 111 and HH 212 protostellar systems- ALMA in Band 7 at ∼ 343 GHz in Cycle 3, with
38-40 antennas in the Configuration C36-6
HH 111 and HH 212
1. diskを解像できている
2. edge-onに近い
3. 若い (散乱のコンタミを減らせる程度に)-> best chance of detecting the poloidal magnetic fieldResults

HH111(early Class 1)

HH212(Class 0)

B direction

・inclination ~ 80°
・polarization fraction of ~ 1%・optically thin・inclination ~ 86°・polarization fraction of ~ 1%・optically thick-> magnetic field lines are mainly
poloidal[in the nearside]・magnetic field is mainly toroidal in the disk
[Near the northern edge of the disk ]・magnetic field lines are poloidal

43. An optical parsec-scale jet from a massive young star in the Large
Magellanic Cloud
McLeod et al. Accepted by Nature

http://arxiv.org/pdf/1801.08147

⼤マゼラン雲(LMC) HH1177に位置するmassive young stellar
object (MYSO) からのoptical ionized jetの直接観測
・LMCにおいて初のjetの観測[Conclusion]
jetの駆動とcollimationの物理過程はstellar massに依存しないDATA・MMYSO ~ 12Msun
・early B-type star・ljet ~ 11 pc (from end to end)・Jet (moving away, Fig 1d red)
3.5 pc, PA ~ 144°
・Jet (moving towards the observer, Fig 1d blue)
6.5 pc, PA ~ -32°
・radial velosity~ 300 - 400 km s-1
・dynamical timescale of jet~ (2.8 - 3.7) x 104 yr
今回のJet-driving MYSOは可視光波⻑領域で⾒える(たいていはembedding
material によって可視光波⻑領域では⾒えない)-> LMCはMilky Wayよりもダスト量が少ないため、星からのionization feedbackが増え、観測しやすくなった？

・mass loss rate of the jet~ 2.9 x 10-6 Msun yr-1
(redとblueの輝線強度のピーク値と推定されたjetの幅から)・accretion rate
~ 9.5 x10-6 Msun yr-1
これらの値から駆動源の年齢が若いことが⽰唆される

HH1177では・Jet⾃体を直接検出-> length-to-harf width ratio, extend and velocityがわかる-> 形状や空間的⽅向がわかる
low mass starsとよく類似(collimation, velosity)-> high mass starからのjetもlow mass star同様は磁気駆動であることをサポートし、stellar massに依存しないことを⽰唆37. Episodic accretion: the interplay of infall and disc instabilities
Kuffmeier et al. Accepted by MNRAS

https://arxiv.org/pdf/1710.00931

39. Bayesian assessment of moving group membership: importanceof models and prior knowledge
Lee & Song. Accepted by MNRAS

http://arxiv.org/pdf/1801.02133

40. Molecular Gas Toward the Gemini OB1 Molecular Cloud Complex
II: CO Outflow Candidates with Possible WISE Associations
Li et al. Accepted by ApJS

http://arxiv.org/pdf/1801.10301

41. Filamentary Fragmentation and Accretion in High-Mass StarForming Molecular Clouds
Lu et al. Accepted by ApJ

https://arxiv.org/pdf/1801.05955

42. Molecular reconnaissance of the β Pictoris gas disk with the SMA:
a low HCN/(CO+CO2) outgassing ratio and predictions for future
surveysMatra et al. Accepted by ApJ

http://arxiv.org/pdf/1801.03945

44. Molecular Gas in Debris Disks around Young A-type Stars
Moor et al. Accepted by ApJ

https://arxiv.org/pdf/1709.08414

45. Candidate Water Vapor Lines to Locate the H2O Snowline ThroughHigh-dispersion Spectroscopic Observations. III. Sub-millimeter H216O
and H218O Lines
Notsu et al. Accepted by ApJ

http://arxiv.org/pdf/1801.07437