A submillimeter view of star formation near the HII region KR 140

Citation
Cr. Kerton et al., A submillimeter view of star formation near the HII region KR 140, ASTROPHYS J, 552(2), 2001, pp. 601-613
Citations number
60
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL JOURNAL
ISSN journal
0004-637X → ACNP
Volume
552
Issue
2
Year of publication
2001
Part
1
Pages
601 - 613
Database
ISI
SICI code
0004-637X(20010510)552:2<601:ASVOSF>2.0.ZU;2-X
Abstract
We present the results of 450 and 850 mum continuum mapping of the H II reg ion KR 140 using the Submillimeter Common-User Bolometer Array (SCUBA) inst rument on the James Clerk Maxwell Telescope (JCMT). KR 140 is a small (5.7 pc diameter) H II region at a distance of 2.3 +/- 0.3 kpc. Five of the six IRAS point sources near KR 140 were mapped in this study. Our analysis show s that two of these IRAS sources are embedded late B-type stars lying well outside the H II region, two are a part of the dust shell surrounding the H II region, and one is the combined emission from an ensemble of smaller so urces unresolved by IRAS. We have discovered a number of relatively cold su bmillimeter sources not visible in the IRAS data, ranging in size from 0.2 to 0.7 pc and in mass from 0.5 to 130 M.. The distribution of masses for al l sources is well characterized by a power law N(>M) proportional to M-alph a with alpha = 0.5 +/- 0.04, in agreement with the typical mass function fo r clumped structures of this scale in molecular clouds. Several of the subm illimeter sources are found at the H II molecular gas interface and have pr obably been formed as the result of the expansion of the H II region. Many of the submillimeter sources we detect are gravitationally bound and most o f these follow a mass-size relationship expected for objects in virial equi librium with nonthermal pressure support. Upon the loss of nonthermal suppo rt, they could be sites of star formation. Along with the two B stars that we have identified as possible cluster members along with VES 735, we argue that five nearby highly reddened stars are in a pre-main-sequence stage of evolution.