Volume 542, June 2012
|Number of page(s)||17|
|Section||Stellar structure and evolution|
|Published online||05 June 2012|
The VLT-FLAMES Tarantula Survey
1 Department of Physics & AstronomyThe Queen’s University of Belfast, BT7 1NN, Northern Ireland, UK
2 Department of Physics and Astronomy, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK
3 Department of Physics & Astronomy, University of Sheffield, Sheffield S3 7RH, UK
4 UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, UK
5 ESA, Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
6 Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland
7 Institute for Astronomy, Royal Observatory Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, UK
8 Armagh Observatory, College Hill, Armagh BT61 9DG, Northern Ireland, UK
Received: 23 January 2012
Accepted: 4 April 2012
Aims. We present an analysis of a peculiar supergiant B-type star (VFTS698/Melnick 2/Parker 1797) in the 30 Doradus region of the Large Magellanic Cloud which exhibits characteristics similar to the broad class of B[e] stars.
Methods. We analyse optical spectra from the VLT-FLAMES survey, together with archival optical and infrared photometry and X-ray imaging to characterise the system.
Results. We find radial velocity variations of around 400 km s-1 in the high excitation Si iv, N iii and He ii spectra, and photometric variability of ~0.6 mag with a period of 12.7 d. In addition, we detect long-term photometric variations of ~0.25 mag, which may be due to a longer-term variability with a period of ~400 d.
Conclusions. We conclude that VFTS698 is likely an interacting binary comprising an early B-type star secondary orbiting a veiled, more massive companion. Spectral evidence suggests a mid-to-late B-type primary, but this may originate from an optically-thick accretion disc directly surrounding the primary.
Key words: stars: early-type / binaries: spectroscopic / stars: peculiar / stars: emission-line, Be / stars: variables: general
Based on observations at the European Southern Observatory Very Large Telescope in programme 182.D-0222.
Table 8 is available in electronic form at http://www.aanda.org
© ESO, 2012
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