Universität zu Köln

Schmalzl, M., Launhardt, R., Stutz, A. M., Linz, H., Bourke, T. L., Beuther, H., Henning, Th., Krause, O., Nielbock, M. and Schmiedeke, A. (2014). The Earliest Phases of Star formation (EPoS) Temperature, density, and kinematic structure of the star-forming core CB 17. Astron. Astrophys., 569. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

Context. The initial conditions for the gravitational collapse of molecular cloud cores and the subsequent birth of stars are still not well constrained. The characteristic cold temperatures (similar to 10 K) in such regions require observations at sub-millimetre and longer wavelengths. The Herschel Space Observatory and complementary ground-based observations presented in this paper have the unprecedented potential to reveal the structure and kinematics of a prototypical core region at the onset of stellar birth. Aims. This paper aims to determine the density, temperature, and velocity structure of the star-forming Bok globule CB 17. This isolated region is known to host (at least) two sources at different evolutionary stages: a dense core, SMM1, and a Class I protostar, IRS. Methods. We modeled the cold dust emission maps from 100 mu m to 1.2mm with both a modified blackbody technique to determine the optical depth-weighted line-of-sight temperature and column density and a ray-tracing technique to determine the core temperature and volume density structure. Furthermore, we analysed the kinematics of CB17 using the high-density gas tracer N2H+. Results. From the ray-tracing analysis, we find a temperature in the centre of SMM1 of T-0 = 10.6K, a flat density profile with radius 9.5 x 10(3) au, and a central volume density of n(H,0) = 2.3 x 10(5) cm(-3). The velocity structure of the N2H+ observations reveal global rotation with a velocity gradient of 4.3 km s(-1) pc(-1). Superposed on this rotation signature we find a more complex velocity field, which may be indicative of differential motions within the dense core. Conclusions. SMM is a core in an early evolutionary stage at the verge of being bound, but the question of whether it is a starless or a protostellar core remains unanswered.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Schmalzl, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Launhardt, R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Stutz, A. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Linz, H. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bourke, T. L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Beuther, H. UNSPECIFIED UNSPECIFIED UNSPECIFIED Henning, Th. UNSPECIFIED UNSPECIFIED UNSPECIFIED Krause, O. UNSPECIFIED UNSPECIFIED UNSPECIFIED Nielbock, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schmiedeke, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-429585
DOI:	10.1051/0004-6361/201322176
Journal or Publication Title:	Astron. Astrophys.
Volume:	569
Date:	2014
Publisher:	EDP SCIENCES S A
Place of Publication:	LES ULIS CEDEX A
ISSN:	1432-0746
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language 1ST HYDROSTATIC CORE; MOLECULAR CLOUD CORES; PRE-STELLAR CORES; PROTOSTELLAR CORES; INITIAL CONDITIONS; HIGH-MASS; PRESTELLAR CORES; DUST-TEMPERATURE; BOK GLOBULES; HERSCHEL OBSERVATIONS Multiple languages Astronomy & Astrophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/42958