A multi-wavelength view on the dusty Wolf-Rayet star WR 48a

Svetozar A. Zhekov (1), Toma Tomov (2), Marcin P. Gawronski (2), Leonid N. Georgiev (3), Jura Borissova (4), Radostin Kurtev (4), Marc Gagne (5) and Marcin Hajduk (6)

(1) Space Research and Technology Institute, Sofia, Bulgaria; (2) Centre for Astronomy, Nicolaus Copernicus University, Torun, Poland; (3) Instituto de Astronomía, Universidad Nacional Autónoma de Mexico, Mexico; (4) Instituto de Fisica y Astronomia, Universidad de Valparaiso, Chile; (5) Department of Geology and Astronomy, West Chester University, West Chester, PA, USA; (6) Nicolaus Copernicus Astronomical Center, Torun, Poland

We present results from the first attempts to derive various physical
characteristics of the dusty Wolf-Rayet star WR 48a based on a
multi-wavelength view of its observational properties. This is done on
the basis of new optical and near-infrared spectral observations and
on data from various archives in the optical, radio and X-rays. The
optical spectrum of WR 48a is acceptably well represented by a sum of
two spectra: of a WR star of the WC8 type and of a WR star of the WN8h
type. The strength of the interstellar absorption features in the
optical spectra of WR 48a and the near-by stars D2-3 and D2-7 (both
members of the open cluster Danks 2) indicates that WR 48a is located
at a distance of ~4 kpc from us. WR 48a is very likely a thermal
radio source and for such a case and smooth (no clumps) wind its radio
emission suggests a relatively high mass-loss rate of this dusty WR
star (dM/dt = a few x 10^(-4) solar masses per year). Long timescale
(years) variability of WR 48a is established in the optical, radio and
X-rays. Colliding stellar winds likely play a very important role in
the physics of this object. However, some LBV-like (luminous blue
variable) activity could not be excluded as well.

Reference: Monthly Notices of the Royal Astronomical Society
Status: Manuscript has been accepted

Weblink: http://arxiv.org/abs/1409.2684


Email: szhekov@space.bas.bg