The RMS survey: The luminosity functions and timescales of massive young stellar objects and compact H II regions

Mottram, Joseph C. and Hoare, Melvin G. and Davies, Ben and Lumsden, Stuart L. and Oudmaijer, Rene D. and Urquhart, J.S. and Moore, Toby J.T. and Cooper, Heather D.B. and Stead, Joseph J. (2011) The RMS survey: The luminosity functions and timescales of massive young stellar objects and compact H II regions. Astrophysical Journal Letters, 730 (2). p. 33. ISSN 2041-8205. (doi:https://doi.org/10.1088/2041-8205/730/2/L33) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. (Contact us about this Publication)
Official URL
http://www.dx.doi.org/10.1088/2041-8205/730/2/L33

Abstract

We present a determination of the luminosity functions of massive young stellar objects (MYSOs) and compact (C) H II regions within the Milky Way using the large, well-selected sample of these sources identified by the Red MSX Source survey. The MYSO luminosity function decreases monotonically such that there are few with Lgsim105 L ☉, while the CH II regions are detected up to ~106 L ☉. The lifetimes of these phases are also calculated as a function of luminosity by comparison with the luminosity function for local main-sequence OB stars. These indicate that the MYSO phase has a duration ranging from 4×105 yr for 104 L ☉ to ~7×104 yr at 105 L ☉, while the CH II region phase lasts of order 3×105 yr or ~3%-10% of the exciting star's main-sequence lifetime. MYSOs between 104 L ☉ and ~105 L ☉ are massive but do not display the radio continuum or near-IR H I recombination line emission indicative of an H II region, consistent with being swollen due to high ongoing or recent accretion rates. Above ~105 L ☉ the MYSO phase lifetime becomes comparable to the main-sequence Kelvin-Helmholtz timescale, at which point the central star can rapidly contract onto the main sequence even if still accreting, and ionize a CH II region, thus explaining why few highly luminous MYSOs are observed.

Item Type: Article
Uncontrolled keywords: Galaxy: stellar content, Hii regions, stars: early-type, stars: formation, stars: luminosity function: mass function, surveys
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Depositing User: James Urquhart
Date Deposited: 30 Nov 2015 16:04 UTC
Last Modified: 30 May 2018 08:49 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/52225 (The current URI for this page, for reference purposes)
Urquhart, J.S.: https://orcid.org/0000-0002-1605-8050
  • Depositors only (login required):