2014A&A...562A.118S


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.18CET08:33:28

2014A&A...562A.118S - Astronomy and Astrophysics, volume 562A, 118-118 (2014/2-1)

The impact of rotation on the line profiles of Wolf-Rayet stars.

SHENAR T., HAMANN W.-R. and TODT H.

Abstract (from CDS):

Massive Wolf-Rayet stars are recognized today to be in a very common, but short, evolutionary phase of massive stars. While our understanding of Wolf-Rayet stars has increased dramatically over the past decades, it remains unclear whether rapid rotators are among them. There are various indications that rapidly rotating Wolf-Rayet stars should exist. Unfortunately, due to their expanding atmospheres, rotational velocities of Wolf-Rayet stars are very difficult to measure. However, recently observed spectra of several Wolf-Rayet stars reveal peculiarly broad and round emission lines. Could these spectra imply rapid rotation? In this work, we model the effects of rotation on the atmospheres of Wolf-Rayet stars. We further investigate whether the peculiar spectra of five Wolf-Rayet stars may be explained with the help of stellar rotation, infer appropriate rotation parameters, and discuss the implications of our results. We make use of the Potsdam Wolf-Rayet (PoWR) non-LTE model atmosphere code. Since the observed spectra of Wolf-Rayet stars are mainly formed in their expanding atmospheres, rotation must be accounted for with a 3D integration scheme of the formal integral. For this purpose, we assume a rotational velocity field consisting of an inner co-rotating domain and an outer domain, where the angular momentum is conserved. We find that rotation can reproduce the unique spectra analyzed here. However, the inferred rotational velocities at the stellar surface are large (∼200km/s), and the inferred co-rotation radii (∼10R*) suggest the existence of very strong photospheric magnetic fields (∼20kG).

Abstract Copyright:

Journal keyword(s): stars: Wolf-Rayet - Magellanic Clouds - stars: magnetic field - stars: massive - gamma-ray burst: general - stars: rotation

Simbad objects: 8

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Number of rows : 8

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 HD 6327 WR* 01 05 23.0143603 +60 25 18.965197   11.49 11.33     WN2-w 104 0
2 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5387 1
3 HD 32109 WR* 04 55 31.3419672483 -67 30 02.683822100 12.893 13.46 13.81 13.95 13.512 WN4b 68 0
4 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14346 1
5 Brey 42 WR* 05 30 02.4528094820 -68 45 18.387450916 14.146 14.939 15.201   15.213 WN3b 28 0
6 Brey 70a WR* 05 37 35.7057107734 -69 08 40.253264123 17.387 17.957 16.924   16.324 WN4b/WCE 24 0
7 HD 269908 WR* 05 38 27.7012451364 -69 29 58.547130741 14.243 14.40 14.29 14.59 14.230 WN4b 39 0
8 HD 270149 WR* 05 46 46.3466957956 -67 09 58.269764283 14.025 14.20 14.48 14.76 14.524 WN4b 48 0

    Equat.    Gal    SGal    Ecl

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2019.11.18-08:33:28

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