标题： X射线脉冲星X1908+075的供体星 显示英文标题

标题： The donor star of the X-ray pulsar X1908+075

摘要： 高质量X射线双星（HMXBs）由一颗大质量供体星和一个致密天体组成。虽然其中一些系统在X射线波段已被深入研究，但对于大多数供体星我们知之甚少，因为它们在光学和紫外波段通常被严重遮蔽。然而，在红外波段观察它们是有机会的。本研究的目标是使用恒星大气模型获取X1908+075高质量X射线双星系统中供体星的恒星和风参数，以验证先前基于X射线观测和光谱形态的研究是否对供体星提供了足够的描述。我们获得了X1908+075的H波段和K波段光谱，并用波茨坦沃尔夫-雷耶（PoWR）模型大气代码对其进行了分析。首次为供体星计算了恒星大气模型，其主要参数为：$M_{\mathrm{spec}}$ = $15 \pm 6$$M_{\odot}$ ， $T_{\ast} = 23_{-3}^{+6},$千开尔文， $\log g_\mathrm{eff} = 3.0 \pm 0.2$和 $\log L/L_{\odot}$ = $4.81 \pm 0.25$。获得的参数表明该星可能是一颗早期B型（B0–B3）星，很可能处于超巨星阶段。 此外，我们得出了该系统更为精确的距离，即 4.85 $\pm$ 0.50 千秒差距，比之前报道的数值更准确。 显示英文摘要

摘要： High-mass X-ray binaries (HMXBs) 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: $M_{\mathrm{spec}}$ = $15 \pm 6$$M_{\odot}$, $T_{\ast} = 23_{-3}^{+6},$kK, $\log g_\mathrm{eff} = 3.0 \pm 0.2$ and $\log L/L_{\odot}$ = $4.81 \pm 0.25$. 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 $\pm$ 0.50 kpc than the previously reported value.