NEW CONSTRAINTS ON THE ORIGIN OF THE SHORT-TERM CYCLICAL VARIABILITY OF THE WOLF-RAYET STAR WR 46
- Scottish Universities Physics Alliance (SUPA), Institute for Astronomy, University of Edinburgh, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)
- Departement de Physique, Universite de Montreal, and Centre de Recherche en Astrophysique du Quebec (CRAQ), C. P. 6128, Succ. Centre-Ville, Montreal, Quebec H3C 3J7 (Canada)
- Science Systems and Applications, Inc., 10210 Greenbelt Road, Suite 600, Lanham, MD 20706 (United States)
- European Space Agency, XMM-Newton Science Operations Centre, ESAC, 28691 Madrid (Spain)
- Research and Scientific Support Department, ESTEC/ESA, P.O. Box 299, 2200, AG Noordwijk (Netherlands)
The Wolf-Rayet star WR 46 is known to exhibit a very complex variability pattern on relatively short timescales of a few hours. Periodic but intermittent radial velocity shifts of optical lines as well as multiple photometric periods have been found in the past. Non-radial pulsations, rapid rotational modulation, or the presence of a putative low-mass companion have been proposed to explain the short-term behavior. In an effort to unveil its true nature, we observed WR 46 with the Far Ultraviolet Spectroscopic Explorer (FUSE) over several short-term variability cycles. We found significant variations on a timescale of {approx}8 hr in the far-ultraviolet (FUV) continuum, in the blue edge of the absorption trough of the O VI {lambda}{lambda}1032, 1038 doublet P Cygni profile and in the S VI {lambda}{lambda}933, 944 P Cygni absorption profile. We complemented these observations with X-ray and UV light curves and an X-ray spectrum from archival X-ray Multi-Mirror Mission-Newton Space Telescope (XMM-Newton) data. The X-ray and UV light curves show variations on a timescale similar to the variability found in the FUV. We discuss our results in the context of the different scenarios suggested to explain the short-term variability of this object and reiterate that non-radial pulsations is the scenario most likely to occur.
- OSTI ID:
- 21576573
- Journal Information:
- Astrophysical Journal, Vol. 735, Issue 1; Other Information: DOI: 10.1088/0004-637X/735/1/13; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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