The donor star of the X-ray pulsar X1908+075
- High-mass X-ray binaries consist of a massive donor star and a compact object. While several of those systems have been well studied in X-rays, little is known for most of the donor stars as they are often heavily obscured in the optical and ultraviolet regime. There is an opportunity to observe them at infrared wavelengths, however. The goal of this study is to obtain the stellar and wind parameters of the donor star in the X1908+075 high-mass X-ray binary system with a stellar atmosphere model to check whether previous studies from X-ray observations and spectral morphology lead to a sufficient description of the donor star. We obtained H-and K-band spectra of X1908+075 and analysed them with the Potsdam Wolf-Rayet (PoWR) model atmosphere code. For the first time, we calculated a stellar atmosphere model for the donor star, whose main parameters are: M-spec = 15 +/- 6 M-circle dot, T-* = 23(-3)(+6) kK, log g(eff) = 3.0 +/- 0.2 and log L/L-circle dot = 4.81 +/- 0.25. The obtained parameters point towards an early B-type (B0-B3) star,High-mass X-ray binaries consist of a massive donor star and a compact object. While several of those systems have been well studied in X-rays, little is known for most of the donor stars as they are often heavily obscured in the optical and ultraviolet regime. There is an opportunity to observe them at infrared wavelengths, however. The goal of this study is to obtain the stellar and wind parameters of the donor star in the X1908+075 high-mass X-ray binary system with a stellar atmosphere model to check whether previous studies from X-ray observations and spectral morphology lead to a sufficient description of the donor star. We obtained H-and K-band spectra of X1908+075 and analysed them with the Potsdam Wolf-Rayet (PoWR) model atmosphere code. For the first time, we calculated a stellar atmosphere model for the donor star, whose main parameters are: M-spec = 15 +/- 6 M-circle dot, T-* = 23(-3)(+6) kK, log g(eff) = 3.0 +/- 0.2 and log L/L-circle dot = 4.81 +/- 0.25. The obtained parameters point towards an early B-type (B0-B3) star, probably in a supergiant phase. Moreover we determined a more accurate distance to the system of 4.85 +/- 0.50 kpc than the previously reported value.…
Author details: | Silvia Martinez-Nunez, Angelika Sander, Angel Gimenez-Garcia, Ana Gonzalez-Galan, Jose Miguel Torrejon, Carlos Gonzalez-Fernandez, Wolf-Rainer HamannORCiDGND |
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DOI: | https://doi.org/10.1051/0004-6361/201424823 |
ISSN: | 0004-6361 |
ISSN: | 1432-0746 |
Title of parent work (English): | Astronomy and astrophysics : an international weekly journal |
Publisher: | EDP Sciences |
Place of publishing: | Les Ulis |
Publication type: | Article |
Language: | English |
Year of first publication: | 2015 |
Publication year: | 2015 |
Release date: | 2017/03/27 |
Tag: | X-rays: binaries; binaries: close; outflows; stars: individual: X1908+075; stars: massive; stars: winds |
Volume: | 578 |
Number of pages: | 9 |
Funding institution: | Spanish Ministerio de Ciencia e Innovacion [AYA2010-15431]; Spanish Unemployment Agency; Deutsche Forschungsgemeinschaft (DFG) [HA 1455/22]; Spanish MICINN under FPI Fellowship [BES-2011-050874]; Vicerectorat [GRE12-35]; Deutsches Zentrum fur Luft und Raumfahrt (DLR) [FKZ 50 OR 1404]; National Aeronautics and Space Administration; National Science Foundation; International Space Science Institute at Bern, Switzerland |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
Peer review: | Referiert |