Star Formation News Letter:No.309 #28-37
2018.10.26 寺澤祥子
28. Multiplicity of disc-bearing stars in Upper Scorpius and Upper Centaurus-Lupus
29. A large-scale survey of CO and its isotopologues toward the Rosette molecular cloud
30. The formation of peptide-like molecules on interstellar dust grains
31. A Submillimeter Burst of S255IR SMA1 - The Rise And Fall Of Its Luminosity
32. The HH30 edge-on T Tauri star. A rotating and precessing monopolar outflow
scrutinized by ALMA
33. Multiple rings in the transitional disk of GM Aurigae revealed by VLA and ALMA34. Pyroclastic Blowout: Dust Survival in Isolated versus Clustered Supernovae
35. First Results of an ALMA Band 10 Spectral Line Survey of NGC 6334I: Detections ofGlycolaldehyde (HC(O)CH2OH) and a New Compact Bipolar Outflow in HDO and CS
36. A global correlation linking young stars, clouds, and galaxies. Towards a unified view ofstar formation.
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37. Protostellar classification using supervised machine learning algorithms

#32 The HH30 edge-on T Tauri star.
A rotating and precessing monopolar outflow scrutinized by ALMA
F. Louvet, C. Dougados, S. Cabrit, D. Mardones, F. M´enard, B. Tabone4 C. Pinte, and W.R.F. Dent
導入・目的

➢
➢

Class 0 /1 , T Tauri-➢

HSTT Tauri

CO

観測天体
HH30
(T tauri2015~140pc)
ALMA cycle 2 period
7 192015 7 21
Band6(211-275GHz
13-1570m
2

結果

12𝐶𝑂 emission
12𝐶𝑂 emission line➢•➢

6.8km/s

0.1km/s•(11.3km/s < V < 14km/s)
2.6km/s < V < 11.3km/s

0312𝐶𝑂 emission(y = -1.2’’)y=3”➢ y = 0’’➢ 0.36’’ < y < 2’’emission➢ y > 2”

PV4

考察
➢
(𝑁𝐻2 )
𝑁𝐻2➢

2.25 × 1020𝑐𝑚−230K

30au
-30au

250au

5➢

z0.1” < z < 1.75”

250au•z=0.1”z=0.1”•35

0.722au
Vcent Vr sin i
Vcent 0.1km/s
Vr sin i 5.3 10^-4km/s

➢or6

#33

Multiple rings in the transitional disk of GM Aurigae revealed by VLA
and ALMA
Enrique Macias, Catherine C. Espaillat, Alvaro Ribas, Kamber R. Schwarz, Guillem Anglada,
Mayra Osorio, Carlos Carrasco-Gonzalez, Jose F. Gomez and Connor Robinson

導入・目的➢➢➢T Tauri

VLAALMA

観測天体
GM Aurigae (T tauri
VLA
20166171602pc)
観測機器

7ALMA

20Cycle 4(2016150m-10000m

Band7mmspw

0.15"11)15m-890m

Qband (40-50GHz)
0.18”

11Band 7(273-373GHz)
𝐶18 𝑂

J = 3-2

13𝐶𝑂

0. 29”

J = 3-2

0.9mm

0. 20”
7

結果
52.8
56.5

➢
SED~35au➢5➢ ALMA

1,ALMAVLA

emission

2, ALMA()

VLA()

SED

8

考察SED

➢ 2•
•

~40au
2~80au
3➢•➢
➢
•
1.

ALMA

42.5 0.2au

VLATarget

39 1aummmm/cm7mm
2.
9#36 A global correlation linking young stars, clouds, and galaxies.
Towards a unified view of star formation.
I. Mendigutia, C.J. Lada and R.D. Oudmaijer
導入・目的

1.

(SFR)

𝑀𝑑𝑔

➢ 60

Schmidt-Kennicutt(𝑀ሶ 𝑎𝑐𝑐 )2. Class II

𝑀𝑑𝑖𝑠𝑘

➢
手法➢

3962

Class IIpc~ kpc
SFR- 𝑀𝑑𝑔➢Class II

Class 0/I
Class II

SFR−𝑀𝑑𝑔

10考察

1.

SFR
Class IIClass 0/I

1.7
𝑦𝑟 −1

➢

20

SFR

2.
SFR- 𝑀𝑑𝑔

Σ𝑀𝐶𝑆 /𝑀𝑑𝑔
Class 0/I

𝑀𝑑𝑖𝑠𝑘
0.012 <

Mcs/ Mdg <0.34

0.01<Σ𝑀𝐶𝑆 /𝑀𝑑𝑔 <0.35

11Class II,,SFR−𝑀

#28 Multiplicity of disc-bearing stars in Upper Scorpius and Upper
Centaurus-Lupus
Rajika L Kuruwita, Michael Ireland, Aaron Rizzuto, Joao Bento and Christoph Federrath
ABSTRACT
We present observations of disc-bearing stars in Upper Scorpius (US) and Upper Centaurus-Lupus (UCL) with moderate
resolution spectroscopy in order to determine the influence of multiplicity on disc persistence after ∼ 5 20Myr.
Discs were identified using infra-red (IR) excess from the Wide-field Infra-red Survey Explorer (WISE) survey.
Our survey consists of 55 US members and 28 UCL members, using spatial and kinematic information to assign a probability ofmembership.
Spectra are gathered from the ANU 2.3m telescope using the Wide Field Spectrograph (WiFeS) to detect radial velocity
variations that indicate the presence of a companion.
We identify 2 double-lined spectroscopic binaries, both of which have strong IR excess.
We find the binary fraction of disc bearing stars in US and UCL for periods up to 20 years to be 0.06+0.07−0.02 and
0.13+0.06−0.03 respectively.
Based on the multiplicity of field stars, we obtain an expected binary fraction of ∼ 0.12+0.02−0.01 .

The determined binary fractions for disc-bearing stars does not vary significantly from the field, suggesting that the overall
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lifetime of discs may not differ between single and binary star systems.

#29 A large-scale survey of CO and its isotopologues toward the Rosettemolecular cloud
Rajika L Kuruwita, Michael Ireland, Aaron Rizzuto, Joao Bento and Christoph Federrath
ABSTRACT
Using the PMO-13.7m millimeter telescope at Delingha in China, we have conducted a large-scale simultaneous survey of 12CO, 13CO, and C18O
J=1-0 emission toward the Rosette molecular cloud (RMC) region with a sky coverage of 3.5
2.5 deg 2 .
The majority of the emission in the region comes from the RMC complex with velocities lying in the range from -2 km/s to 20.5 km/s.
Beyond this velocity range, 73 molecular clumps are identified with kinematic distances from 2.4 kpc to 11 kpc.
Based on the spatial and velocity distribution, nine individual clouds, C1-C9, have been identified for the RMC complex.
It appears that the C3 cloud is different from other clouds in the RMC complex in view of its characteristic velocity, excitation temperature, andvelocity dispersion.
Most of the young stellar clusters in the region are located in positions of both high column density and high excitation temperature.

Seven new molecular filaments are discovered in the RMC complex.
Evidence for cloud-cloud collision is found in the region of young stellar clusters REFL9 and PouF, showing that these young stellar clusters
probably result from a cloud-cloud collision.
The abundance ratios of 13CO to C18O in the region have a mean value of 13.7 which is 2.5 times larger than the solar system value, showing that13
UV photons from the nearby OB clusters have strong influence on the chemistry of clouds in the RMC complex.

#30 The formation of peptide-like molecules on interstellar dust grains
N.F.W. Ligterink, J. Terwisscha van Scheltinga, V. Taquet, J.K. Jørgensen, S. Cazaux,
E.F.van Dishoeck and H. Linnartz
ABSTRACT
Molecules with an amide functional group resemble peptide bonds, the molecular bridges that connect amino acids, and may thus be relevant inprocesses that lead to the formation of life.
In this study, the solid state formation of some of the smallest amides is investigated in the laboratory.
To this end, CH4:HNCO ice mixtures at 20 K are irradiated with far-UV photons, where the radiation is used as a tool to produce the radicals
required for the formation of the amides.
Products are identified and investigated with infrared spectroscopy and temperature programmed desorption mass spectrometry.
The laboratory data show that NH2CHO, CH3NCO, NH2C(O)NH2, CH3C(O)NH2 and CH3NH2 can simultaneously be formed. The NH2CO radicalis found to be key in the formation of larger amides.
In parallel, ALMA observations towards the low-mass protostar IRAS 16293 2422B are analysed in search of CH3NHCHO (N-methylformamide)
and CH3C(O)NH2 (acetamide).
CH3C(O)NH2 is tentatively detected towards IRAS 16293 2422B at an abundance comparable with those found towards high-mass sources.
The combined laboratory and observational data indicates that NH2CHO and CH3C(O)NH2 are chemically linked and form in the ice mantles ofinterstellar dust grains.
A solid-state reaction network for the formation of these amides is proposed.

14#31 A Submillimeter Burst of S255IR SMA1 - The Rise And Fall Of ItsLuminosity
Sheng-Yuan Liu, Yu-Nung Su, Igor Zinchenko, Kuo-Song Wang, and Yuan Wang
ABSTRACT
Temporal photometric variations at near infrared to submillimeter wavelengths have been found in low-mass
young stellar objects.
These phenomena are generally interpreted as accretion events of star-disk systems with varying accretion rates.
There is growing evidence suggesting that similar luminosity flaring also occurs in high-mass star/clusterforming
regions.
We report in this Letter the rise and fall of the 900 m continuum emission and the newly found 349.1 GHz
methanol maser emission in the massive star forming region S255IR SMA1 observed with the Submillimeter Array
and the Atacama Large Millimeter/submillimeter Array.
The level of flux variation at a factor of ∼2 at the submillimeter band and the relatively short 2-year duration ofthis burst suggest that the event is probably similar to those milder and more frequent minor bursts seen in 3D
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numerical simulations.

#34 Pyroclastic Blowout : Dust Survival in Isolated versus Clustered SupernovaeSergio Martinez-Gonzalez, Richard Wunsch, Jan Palous, Casiana Munoz-Tunon, Sergiy Silichand Guillermo Tenorio-Tagle
ABSTRACT
Following the current debate on the fate of SN-#35 First Results of an ALMA Band 10 Spectral Line Survey of NGC 6334I: Detections ofGlycolaldehyde (HC(O)CH2OH) and a New Compact Bipolar Outflow in HDO and CS
Brett A. McGuire, Crystal L. Brogan, Todd R. Hunter, Anthony J. Remijan, Geoffrey A. Blake,Andrew M. Burkhardt, P. Brandon Carroll,Ewine F. van Dishoeck, Robin T. Garrod, Harold Linnartz, Christopher N. Shingledecker and Eric R. WillisABSTRACT
We present the first results of a pilot program to conduct an ALMA Band 10 spectral line survey of the high-mass star-forming region
NGC6334I.
The observations were taken in exceptional weather conditions (0.19 mm precipitable water) with typical system temperatures Tsys
<950 K at ~890 GHz.
A bright, bipolar north-south outflow is seen in HDO and CS emission, driven by the embedded massive protostar MM1B.
This has allowed, for the first time, a direct comparison of the thermal water in this outflow to the location of water maser emission fromprior 22 GHz VLA observations.
The maser locations are shown to correspond to the sites along the outflow cavity walls where high velocity gas impacts the surroundingmaterial.
We also compare our new observations to prior Herschel HIFI spectral line survey data of this field, detecting an order of magnitude
more spectral lines (695 vs 65) in the ALMA data.
We focus on the strong detections of the complex organic molecule glycolaldehyde (HC(O)CH2OH) in the ALMA data that is notdetected in the heavily beam-diluted HIFI spectra. Finally, we stress the need for dedicated THz laboratory spectroscopy to support and17
exploit future high-frequency molecular line observations with ALMA.

#37 Protostellar classification using supervised machine learning algorithms
Oskari Miettinen
ABSTRACTClassification of young stellar objects (YSOs) into different evolutionary stages helps us to understand the formation process of new stars and planetary systems.
Such classification has traditionally been based on spectral energy distribution (SED) analysis. An alternative approach is provided by supervised machine learningalgorithms, which can be trained to classify large samples of YSOs much faster than via SED analysis.

We attempt to classify a sample of Orion YSOs (the parent sample size is 330) into different classes, where each source has already been classified using
multiwavelength SED analysis.
We used eight different learning algorithms to classify the target YSOs, namely a decision tree, random forest, gradient boosting machine (GBM), logistic regression, naive
Bayes classifier, k-nearest neighbour classifier, support vector machine, and neural network.
The classifiers were trained and tested by using a 10-fold cross-validation procedure. As the learning features, we employed ten different continuum flux densities
spanning from the near-infrared to submillimetre wavebands (3.6 - 870 m).
With a classification accuracy of 82% (with respect to the SED-based classes), a GBM algorithm was found to exhibit the best performance. The lowest accuracy of 47%
was obtained with a nave Bayes classifier.
Our analysis suggests that the inclusion of the 3.6m and 24m flux densities is useful to maximise the YSO classification accuracy.

Although machine learning has the potential to provide a rapid and fairly reliable way to classify YSOs, an SED analysis is still needed to derive the physical properties ofthe sources (e.g. dust temperature and mass), and to create the labelled training data.
The machine learning classification accuracies can be improved with respect to the present results by using larger data sets, more detailed missing value imputation, andadvanced ensemble methods (e.g. extreme gradient boosting).
Overall, the application of machine learning is expected to be very useful in the era of big astronomical data, for example to quickly assemble interesting target source
samples for follow-up studies.
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