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Title: SUBSTELLAR-MASS CONDENSATIONS IN PRESTELLAR CORES

Abstract

We present combined Submillimeter Array and single-dish images of the (sub)millimeter dust continuum emission toward two prestellar cores, SM1 and B2-N5, in the nearest star-cluster-forming region, {rho} Ophiuchus. Our combined images indicate that SM1 and B2-N5 consist of three and four condensations, respectively, with masses of 10{sup -2}-10{sup -1} M{sub Sun} and sizes of a few hundred AU. The individual condensations have mean densities of 10{sup 8}-10{sup 9} cm{sup -3} and the masses are comparable to or larger than the critical Bonner-Ebert mass, indicating that self-gravity plays an important role in the dynamical evolution of the condensations. The coalescence timescale of these condensations is estimated to be about 10{sup 4} yr, which is comparable to the local gravitational collapse timescale, suggesting that merging of the condensations, instead of accretion, plays an essential role in the star formation process. These results challenge the standard theory of star formation, where a single, rather featureless, prestellar core collapses to form at most a couple of condensations, each of which potentially evolves into a protostar that is surrounded by a rotating disk where planets are created.

Authors:
;  [1];  [2]
  1. National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan)
  2. Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 106, Taiwan (China)
Publication Date:
OSTI Identifier:
22078490
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 758; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COALESCENCE; DENSITY; GRAVITATIONAL COLLAPSE; IMAGES; MASS; PLANETS; STAR CLUSTERS; STARS; TIME DEPENDENCE

Citation Formats

Nakamura, Fumitaka, Kawabe, Ryohei, and Takakuwa, Shigehisa, E-mail: fumitaka.nakamura@nao.ac.jp. SUBSTELLAR-MASS CONDENSATIONS IN PRESTELLAR CORES. United States: N. p., 2012. Web. doi:10.1088/2041-8205/758/2/L25.
Nakamura, Fumitaka, Kawabe, Ryohei, & Takakuwa, Shigehisa, E-mail: fumitaka.nakamura@nao.ac.jp. SUBSTELLAR-MASS CONDENSATIONS IN PRESTELLAR CORES. United States. doi:10.1088/2041-8205/758/2/L25.
Nakamura, Fumitaka, Kawabe, Ryohei, and Takakuwa, Shigehisa, E-mail: fumitaka.nakamura@nao.ac.jp. Sat . "SUBSTELLAR-MASS CONDENSATIONS IN PRESTELLAR CORES". United States. doi:10.1088/2041-8205/758/2/L25.
@article{osti_22078490,
title = {SUBSTELLAR-MASS CONDENSATIONS IN PRESTELLAR CORES},
author = {Nakamura, Fumitaka and Kawabe, Ryohei and Takakuwa, Shigehisa, E-mail: fumitaka.nakamura@nao.ac.jp},
abstractNote = {We present combined Submillimeter Array and single-dish images of the (sub)millimeter dust continuum emission toward two prestellar cores, SM1 and B2-N5, in the nearest star-cluster-forming region, {rho} Ophiuchus. Our combined images indicate that SM1 and B2-N5 consist of three and four condensations, respectively, with masses of 10{sup -2}-10{sup -1} M{sub Sun} and sizes of a few hundred AU. The individual condensations have mean densities of 10{sup 8}-10{sup 9} cm{sup -3} and the masses are comparable to or larger than the critical Bonner-Ebert mass, indicating that self-gravity plays an important role in the dynamical evolution of the condensations. The coalescence timescale of these condensations is estimated to be about 10{sup 4} yr, which is comparable to the local gravitational collapse timescale, suggesting that merging of the condensations, instead of accretion, plays an essential role in the star formation process. These results challenge the standard theory of star formation, where a single, rather featureless, prestellar core collapses to form at most a couple of condensations, each of which potentially evolves into a protostar that is surrounded by a rotating disk where planets are created.},
doi = {10.1088/2041-8205/758/2/L25},
journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 2,
volume = 758,
place = {United States},
year = {2012},
month = {10}
}