A radiation driven implosion model for the enhanced luminosity of protostars near HII regions

Free access article

Issue		A&A Volume 467, Number 2, May IV 2007


Page(s)		657 - 664
Section		Stellar structure and evolution
DOI		http://dx.doi.org/10.1051/0004-6361:20067042

A&A 467, 657-664 (2007)
DOI: 10.1051/0004-6361:20067042

A radiation driven implosion model for the enhanced luminosity of protostars near HII regions

K. Motoyama¹, T. Umemoto², and H. Shang³

¹ Theoretical Institute for Advanced Research in Astrophysics, Dept. of Physics, National Tsing Hua University, 101, Sec. 2, Kuang-Fu Rd., Hsin-Chu, 30013, Taiwan
e-mail: motoyama@tiara.sinica.edu.tw
² Nobeyama Radio Observatory, Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305, Japan
³ Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 106, Taiwan

(Received 29 December 2006 / Accepted 7 February 2007 )

Abstract
Context.Molecular clouds near $\ion{H}{ii}$ regions tend to harbor more luminous protostars.
Aims.We investigate whether a radiation-driven implosion mechanism enhances the luminosity of protostars near regions of high ionizing fluxes.
Methods.We performed numerical simulations to model collapse of cores exposed to UV radiation from O stars. We investigated the dependence of mass loss rates on the initial density profiles of cores and variation of UV fluxes. We derived simple analytic estimates of accretion rates and final masses of protostars.
Results.The radiation-driven implosion mechanism can increase accretion rates of protostars by 1-2 orders of magnitude. On the other hand, mass loss due to photo-evaporation is not high enough to have a significant impact on the luminosity. The increase in accretion rate results in luminosity 1-2 orders of magnitude higher than those of protostars that form without external triggering.
Conclusions.Radiation-driven implosion can help explain the observed higher luminosity of protostars in molecular clouds near $\ion{H}{ii}$ regions.

Key words: stars: formation -- ISM: HII regions -- methods: numerical

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.