Universität zu Köln

Naranjo-Romero, Raul, Zapata, Luis A., Vazquez-Semadeni, Enrique ORCID: 0000-0002-1424-3543, Takahashi, Satoko, Palau, Aina ORCID: 0000-0002-9569-9234 and Schilke, Peter (2012). FROM DUSTY FILAMENTS TO MASSIVE STARS: THE CASE OF NGC 7538 S. Astrophys. J., 757 (1). BRISTOL: IOP PUBLISHING LTD. ISSN 0004-637X

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Abstract

We report on high-sensitivity and high angular resolution archival Submillimeter Array observations of the large (similar to 15,000 AU) putative circumstellar disk associated with the O-type protostar NGC 7538 S. Observations of the continuum resolve this putative circumstellar disk into five compact sources, with sizes similar to 3000 AU and masses similar to 10 M-circle dot. This confirms the results of recent millimeter observations made with CARMA/BIMA toward this object. However, we find that most of these compact sources eject collimated bipolar outflows, revealed by our silicon monoxide (SiO J = 5-4) observations, and confirm that these sources have a (proto) stellar nature. All outflows are perpendicular to the large and rotating dusty structure. We propose therefore that, rather than being a single massive circumstellar disk, NGC 7538 S could instead be a large and massive contracting or rotating filament that is fragmenting at scales of 0.1-0.01 pc to form several B-type stars, via the standard process involving outflows and disks. As in recent high spatial resolution studies of dusty filaments, our observations also suggest that thermal pressure does not seem to be sufficient to support the filament, so that either additional support needs to be invoked or else the filament must be in the process of collapsing. A smoothed particle hydrodynamics numerical simulation of the formation of a molecular cloud by converging warm neutral medium flows produces contracting filaments whose dimensions and spacings between the stars forming within them, as well as their column densities, strongly resemble those observed in the filament reported here.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Naranjo-Romero, Raul UNSPECIFIED UNSPECIFIED UNSPECIFIED Zapata, Luis A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Vazquez-Semadeni, Enrique UNSPECIFIED orcid.org/0000-0002-1424-3543 UNSPECIFIED Takahashi, Satoko UNSPECIFIED UNSPECIFIED UNSPECIFIED Palau, Aina UNSPECIFIED orcid.org/0000-0002-9569-9234 UNSPECIFIED Schilke, Peter UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-482839
DOI:	10.1088/0004-637X/757/1/58
Journal or Publication Title:	Astrophys. J.
Volume:	757
Number:	1
Date:	2012
Publisher:	IOP PUBLISHING LTD
Place of Publication:	BRISTOL
ISSN:	0004-637X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language MOLECULAR OUTFLOW; SUBMILLIMETER ARRAY; PROTOSTELLAR CORES; FORMING REGIONS; FRAGMENTATION; DISK; SIO; G28.34+0.06; ACCRETION; DISCOVERY Multiple languages Astronomy & Astrophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/48283