scholarly journals Distribution of Serpens South protostars revealed with ALMA

2018 ◽  
Vol 615 ◽  
pp. A9 ◽  
Author(s):  
Adele L. Plunkett ◽  
Manuel Fernández-López ◽  
Héctor G. Arce ◽  
Gemma Busquet ◽  
Diego Mardones ◽  
...  
Keyword(s):  
Star Formation ◽  
Minimum Spanning Tree ◽  
Cluster Center ◽  
Mass Star ◽  
Filamentary Structure ◽  
First Case ◽  
Low Mass ◽  
Mass Segregation ◽  
The Masses ◽  
Mass Sources

Context. Clusters are common sites of star formation, whose members display varying degrees of mass segregation. The cause may be primordial or dynamical, or a combination both. If mass segregation were to be observed in a very young protostellar cluster, then the primordial case can be assumed more likely for that region. Aims. We investigated the masses and spatial distributions of pre-stellar and protostellar candidates in the young, low-mass star forming region Serpens South, where active star formation is known to occur along a predominant filamentary structure. Previous observations used to study these distributions have been limited by two important observational factors: (1) sensitivity limits that leave the lowest-mass sources undetected or (2) resolution limits that cannot distinguish binaries and/or cluster members in close proximity. Methods. Recent millimeter-wavelength interferometry observations can now uncover faint and/or compact sources in order to study a more complete population of protostars, especially in nearby (D < 500 pc) clusters. Here we present ALMA observations of 1 mm (Band 6) continuum in a 3 × 2 arcmin region at the center of Serpens South. Our angular resolution of ~1′′ is equivalent to ~400 au, corresponding to scales of envelopes and/or disks of protostellar sources. Results. We detect 52 sources with 1 mm continuum, and we measure masses of 0.002–0.9 solar masses corresponding to gas and dust in the disk and/or envelope of the protostellar system. For the deeply embedded (youngest) sources with no IR counterparts, we find evidence of mass segregation and clustering according to: the minimum spanning tree method, distribution of projected separations between unique sources, and concentration of higher-mass sources near to the dense gas at the cluster center. Conclusions. The mass segregation of the mm sources is likely primordial rather than dynamical given the young age of this cluster, compared with segregation time. This is the first case to show this for mm sources in a low-mass protostellar cluster environment.

scholarly journals Massive and low-mass protostars in massive “starless” cores

2019 ◽  
Vol 622 ◽  
pp. A54 ◽  
Author(s):  
Thushara Pillai ◽  
Jens Kauffmann ◽  
Qizhou Zhang ◽  
Patricio Sanhueza ◽  
Silvia Leurini ◽  
...  
Keyword(s):  
Star Formation ◽  
Detection Limit ◽  
High Mass ◽  
Mass Star ◽  
Core Mass ◽  
Filamentary Structure ◽  
Dark Clouds ◽  
Low Mass ◽  
Infrared Dark Clouds ◽  
Dense Clump

The infrared dark clouds (IRDCs) G11.11−0.12 and G28.34+0.06 are two of the best-studied IRDCs in our Galaxy. These two clouds host clumps at different stages of evolution, including a massive dense clump in both clouds that is dark even at 70 and 100 μm. Such seemingly quiescent massive dense clumps have been speculated to harbor cores that are precursors of high-mass stars and clusters. We observed these two “prestellar” regions at 1 mm with the Submillimeter Array (SMA) with the aim of characterizing the nature of such cores. We show that the clumps fragment into several low- to high-mass cores within the filamentary structure of the enveloping cloud. However, while the overall physical properties of the clump may indicate a starless phase, we find that both regions host multiple outflows. The most massive core though 70 μm dark in both clumps is clearly associated with compact outflows. Such low-luminosity, massive cores are potentially the earliest stage in the evolution of a massive protostar. We also identify several outflow features distributed in the large environment around the most massive core. We infer that these outflows are being powered by young, low-mass protostars whose core mass is below our detection limit. These findings suggest that low-mass protostars have already formed or are coevally formed at the earliest phase of high-mass star formation.

scholarly journals Wave dynamics and star formation in Taurus

1991 ◽  
Vol 147 ◽  
pp. 317-327
Author(s):  
Ralph E. Pudritz ◽  
Ana I. Gomez de Castro
Keyword(s):  
Star Formation ◽  
Young Stellar Objects ◽  
Mass Star ◽  
Stellar Objects ◽  
Filamentary Structure ◽  
Dark Clouds ◽  
Ideal Object ◽  
Wave Dynamics ◽  
Low Mass ◽  
Optical Photograph

The mechanism underlying the formation of cores and larger scale structures in molecular clouds must play a fundamental role in the physics of star formation since young stellar objects are usually found within or very near cores (Myers et al 1987, Beichman et al 1986). The Taurus cloud is an ideal object to study in this regard because of its proximity (160 pc), and because only low mass star formation is presently occurring there. Barnard's (1927) beautiful optical photograph of the region reveals that the obscuring gas and dust has filamentary structure that is comparable to the size of the cloud complex (several 10's of pc). This structure is clearly seen in CO maps of the region as well (eg. Duvert et al 1986) where it is apparent that structure on much larger size scales than cores is common. In addition to the filamentary structure one also observes that there are small dark clouds present such as L1489, L1495, etc.

scholarly journals Wave dynamics and star formation in Taurus

1991 ◽  
Vol 147 ◽  
pp. 317-327
Author(s):  
Ralph E. Pudritz ◽  
Ana I. Gomez de Castro
Keyword(s):  
Star Formation ◽  
Young Stellar Objects ◽  
Mass Star ◽  
Stellar Objects ◽  
Filamentary Structure ◽  
Dark Clouds ◽  
Ideal Object ◽  
Wave Dynamics ◽  
Low Mass ◽  
Optical Photograph

The mechanism underlying the formation of cores and larger scale structures in molecular clouds must play a fundamental role in the physics of star formation since young stellar objects are usually found within or very near cores (Myers et al 1987, Beichman et al 1986). The Taurus cloud is an ideal object to study in this regard because of its proximity (160 pc), and because only low mass star formation is presently occurring there. Barnard's (1927) beautiful optical photograph of the region reveals that the obscuring gas and dust has filamentary structure that is comparable to the size of the cloud complex (several 10's of pc). This structure is clearly seen in CO maps of the region as well (eg. Duvert et al 1986) where it is apparent that structure on much larger size scales than cores is common. In addition to the filamentary structure one also observes that there are small dark clouds present such as L1489, L1495, etc.

Low‐Mass Star Formation and the Initial Mass Function in IC 348

1998 ◽  
Vol 508 (1) ◽  
pp. 347-369 ◽  
Author(s):  
K. L. Luhman ◽  
G. H. Rieke ◽  
C. J. Lada ◽  
E. A. Lada
Keyword(s):  
Star Formation ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Mass Star ◽  
Low Mass

scholarly journals The effect of episodic accretion on the phase transition of CO and CO2in low-mass star formation

2013 ◽  
Vol 557 ◽  
pp. A35 ◽  
Author(s):  
Eduard I. Vorobyov ◽  
Isabelle Baraffe ◽  
Tim Harries ◽  
Gilles Chabrier
Keyword(s):  
Phase Transition ◽  
Star Formation ◽  
Mass Star ◽  
Low Mass

scholarly journals FEEDBACK EFFECTS ON LOW-MASS STAR FORMATION

2012 ◽  
Vol 747 (1) ◽  
pp. 22 ◽  
Author(s):  
Charles E. Hansen ◽  
Richard I. Klein ◽  
Christopher F. McKee ◽  
Robert T. Fisher
Keyword(s):  
Star Formation ◽  
Mass Star ◽  
Feedback Effects ◽  
Low Mass

scholarly journals Submillimeter Array Observations of Magnetic Fields in Star Forming Regions

2010 ◽  
Vol 6 (S270) ◽  
pp. 103-106
Author(s):  
R. Rao ◽  
J.-M. Girart ◽  
D. P. Marrone
Keyword(s):  
Magnetic Field ◽  
Star Formation ◽  
Magnetic Fields ◽  
Computational Models ◽  
Dominant Role ◽  
Theoretical Models ◽  
Mass Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
Low Mass

AbstractThere have been a number of theoretical and computational models which state that magnetic fields play an important role in the process of star formation. Competing theories instead postulate that it is turbulence which is dominant and magnetic fields are weak. The recent installation of a polarimetry system at the Submillimeter Array (SMA) has enabled us to conduct observations that could potentially distinguish between the two theories. Some of the nearby low mass star forming regions show hour-glass shaped magnetic field structures that are consistent with theoretical models in which the magnetic field plays a dominant role. However, there are other similar regions where no significant polarization is detected. Future polarimetry observations made by the Submillimeter Array should be able to increase the sample of observed regions. These measurements will allow us to address observationally the important question of the role of magnetic fields and/or turbulence in the process of star formation.

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