EDP Sciences
Free Access
Issue
A&A
Volume 431, Number 3, March I 2005
Page(s) 993 - 1005
Section Interstellar and circumstellar matter
DOI https://doi.org/10.1051/0004-6361:20041595


A&A 431, 993-1005 (2005)
DOI: 10.1051/0004-6361:20041595

Subarcsecond mid-infrared and radio observations of the W3 IRS5 protocluster

F. F. S. van der Tak1, P. G. Tuthill2 and W. C. Danchi3

1  Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
    e-mail: vdtak@mpifr-bonn.mpg.de
2  School of Physics, University of Sydney, NSW 2006, Australia
3  NASA Goddard Space Flight Center, Infrared Astrophysics, Code 685, Greenbelt MD 20771, USA

(Received 5 July 2004 / Accepted 27 October 2004 )

Abstract
Observations at mid-infrared (4.8-17.65  $\mu$m) and radio (0.7-1.3 cm) wavelengths are used to constrain the structure of the high-mass star-forming region W3 IRS5 on 0 $\farcs$1 (200 AU) scales. Two bright mid-infrared sources are detected, as well as diffuse emission. The bright sources have associated compact radio emission and probably are young high-mass stars. The measured sizes and estimated temperatures indicate that these sources together can supply the observed far-infrared luminosity. However, an optically thick radio source with a possible mid-infrared counterpart may also contribute significant luminosity; if so, it must be extremely deeply embedded. The infrared colour temperatures of 350-390 K and low radio brightness suggest gravitational confinement of the H II regions and ongoing accretion at a rate of a few 10 -8  $M_{\odot}$ yr -1 or more. Variations in the accretion rate would explain the observed radio variability. The low estimated foreground extinction suggests the existence of a cavity around the central stars, perhaps blown by stellar winds. At least three radio sources without mid-infrared counterparts appear to show proper motions of ~100 km s -1, and may be deeply embedded young runaway OB stars, but more likely are clumps in the ambient material which are shock-ionized by the OB star winds.


Key words: stars: circumstellar matter -- stars: formation -- instrumentation: high angular resolution -- ISM: individual objects: W3 IRS5

SIMBAD Objects



© ESO 2005

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.