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The optical counterpart to the peculiar X-ray transient XTE J1739-302

Ignacio Negueruela·David M. Smith·Thomas E. Harrison·Jose Miguel Torrejon
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Abstract

The weak X-ray transient XTE J1739-302, characterized by extremely short outbursts, has recently been identified with a reddened star. Here we present spectroscopy and photometry of the counterpart, identifying it as a O8Iab(f) supergiant at a distance of ~2.3 kpc. XTE J1739-302 becomes thus characterized as the prototype of the new class of Supergiant Fast X-ray Transients. The optical and infrared spectra of the counterpart to XTE J1739-302 do not reveal any obvious characteristics setting it apart from other X-ray binaries with supergiant companions, which display a very different type of X-ray lightcurve.

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Ignacio Negueruela, David M. Smith, Thomas E. Harrison, Jose Miguel Torrejon. 2005-10-24. The optical counterpart to the peculiar X-ray transient XTE J1739-302. https://doi.org/10.1086/498935

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