Volume 436, Number 2, June III 2005
|Page(s)||661 - 669|
|Section||Stellar structure and evolution|
|Published online||30 May 2005|
VLT/UVES spectroscopy of the O supergiant companion to 4U 1907+09(7)
Astronomical Institute “Anton Pannekoek”, University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands e-mail: email@example.com
Accepted: 2 March 2005
High-resolution optical spectra of the high-mass X-ray binary 4U 1907+09 covering the wavelength range 4680-10 400 Å indicate that the X-ray pulsar's massive companion is an O8/O9 supergiant with a dense stellar wind. The interstellar atomic lines of and of this strongly reddened source ( mag) are used to set a lower limit to its distance: kpc, excluding the possibility that the massive companion is a Be star. We re-evaluate the system parameters; the new spectral classification of 4U 1907+09's O supergiant companion is discussed in the context of its similarity in X-ray and orbital properties to Wray 15-977/GX 301-2. The Hα line shows variability similar to what is observed in other wind-fed systems. A remarkable feature is the strong He ii 4686 Å emission line, which possibly originates in the accretion flow towards the X-ray pulsar.
Key words: stars: binaries: close / stars: early-type / stars: winds, outflows / X-rays: individual: 4U 1907+09 / ISM: lines and bands
© ESO, 2005
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.