The physical and dynamical structure of Serpens. Two very different sub-(proto)clusters
Abstract
Context. The Serpens North cluster is a nearby low mass star forming region which is part of the Gould belt. It contains a range of young stars thought to correspond to two different bursts of star formation and provides the opportunity to study different stages of cluster formation.
Aims: This work aims to study the molecular gas in the Serpens North cluster to probe the origin of the most recent burst of star formation in Serpens.
Methods: Transitions of the C17O and C18O observed with the IRAM 30 m telescope and JCMT are used to study the mass and velocity structure of the region while the physical properties of the gas are derived using LTE and non-LTE analyses of the three lowest transitions of C18O.
Results: The molecular emission traces the two centres of star formation which are seen in submillimetre dust continuum emission. In the ~40 M_⊙ NW sub-cluster the gas and dust emission trace the same structures although there is evidence of some depletion of the gas phase C18O. The gas has a very uniform temperature (~10 K) and velocity (~8.5 km s-1) throughout the region. This is in marked contrast to the SE sub-cluster. In this region the dust and the gas trace different features, with the temperature peaking between the submillimetre continuum sources, reaching up to ~14 K. The gas in this region has double peaked line profiles which reveal the presence of a second cloud in the line of sight. The submillimetre dust continuum sources predominantly appear located in the interface region between the two clouds.
Conclusions: Even though they are at a similar stage of evolution, the two Serpens sub-clusters have very different characteristics. We propose that these differences are linked to the initial trigger of the collapse in the regions and suggest that a cloud-cloud collision could explain the observed properties.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 2010
- DOI:
- 10.1051/0004-6361/200913919
- arXiv:
- arXiv:1006.0879
- Bibcode:
- 2010A&A...519A..27D
- Keywords:
-
- stars: formation;
- ISM: kinematics and dynamics;
- ISM: molecules;
- ISM: clouds;
- ISM: structure;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- Accepted for publication in A&