EDP Sciences
Free access
Volume 397, Number 2, January II 2003
Page(s) 739 - 745
Section Stellar atmospheres
DOI http://dx.doi.org/10.1051/0004-6361:20021529

A&A 397, 739-745 (2003)
DOI: 10.1051/0004-6361:20021529

The Be/X-ray transient KS 1947+300

I. Negueruela1, 2, G. L. Israel3, A. Marco2, A. J. Norton4 and R. Speziali3

1  Observatoire de Strasbourg, 11 rue de l'Université, 67000 Strasbourg, France
2  Dpto. de Física, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante, Apdo. de Correos 99, E03080 Alicante, Spain
3  Osservatorio Astronomico di Roma, via Frascati 33, I00040 Monteporzio Catone, Italy
4  Department of Physics & Astronomy, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK

(Received 19 July 2002 / Accepted 18 October 2002 )

We present optical spectroscopy and optical and infrared photometry of the counterpart to the transient X-ray source KS 1947+300 . The counterpart is shown to be a moderately reddened V=14.2 early-type Be star located in an area of low interstellar absorption slightly above the Galactic plane. Changes in brightness are accompanied by correlated reddening of the source, as is expected in this kind of object. From intermediate resolution spectroscopy, we derive a spectral type B0Ve. If the intrinsic luminosity of the star is normal for its spectral type, KS 1947+300 is situated at a distance of ~10 kpc, implying that its X-ray luminosity at the peak of the spring 2000 X-ray outburst was typical of Type II outbursts in Be/X-ray transients. KS 1947+300 is thus the first Be/X-ray recurrent transient showing Type II outbursts which has an almost circular orbit.

Key words: stars: emission line, Be -- stars: individual: KS 1947+300 -- stars: binaries: close -- stars: neutron -- X-ray: stars

Offprint request: I. Negueruela, ignacio@disc.ua.es

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© ESO 2003