A&A 413, L15-L18 (2004)
DOI: 10.1051/0004-6361:20031700

Letter

A newly identified Luminous Blue Variable in the galactic starburst cluster Westerlund 1

J. S. Clark¹ and I. Negueruela<sup>2

1</sup>  Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT, England, UK
²  Dpto. de Física, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante, Apdo. 99, E03080 Alicante, Spain

(Received 11 November 2003 / Accepted 27 November 2003 )

Abstract
We present observations of the massive transitional star W243 in Westerlund 1 . We find an apparent spectral type of early-mid A from our data, in contrast to an earlier classification of B2I, made from data obtained in 1981. The concurrent development of a rich emission line spectrum suggests a very high mass loss rate; the continued presence of He I emission suggesting that the underlying star remains significantly hotter than implied by its apparent spectral type. We suggest that W243 is a Luminous Blue Variable undergoing an eruptive phase, leading to an extreme mass loss rate and the formation of a pseudo photosphere.

Key words: stars: evolution -- stars: variables: general -- winds, outflows -- supergiants

Offprint request: J. S. Clark, jsc@star.ucl.ac.uk

SIMBAD Objects in preparation

© ESO 2004

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