Optical spectra of the carbon-oxygen accretion discs in the ultra-compact X-ray binaries 4U 0614+09, 4U 1543-624 and 2S 0918-549
Optical spectra of the carbon-oxygen accretion discs in the ultra-compact X-ray binaries 4U 0614+09, 4U 1543-624 and 2S 0918-549
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DOI：
10.1111/j.1365-2966.2004.07486.x
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发表时间：
2003-12
影响因子：
4.8
通讯作者：
G. Nelemans;P. Jonker;T. R. Marsh;M. Klis
中科院分区：
文献类型：
--
作者：
G. Nelemans;P. Jonker;T. R. Marsh;M. Klis
我们展示了三个低质量 X 射线双星在 4600‐8600°A 范围内的光谱，根据其 X 射线光谱，这些双星被认为属于超紧凑 X 射线双星类别。我们的光谱没有显示出氢或氦发射线的证据，如经典 X 射线双星中所见。 4U 0614+09 的光谱确实显示了发射线，我们将其与 C II 、C III 、O II 和 O III 的碳线和氧线识别。虽然 4U 1543−624 和 2S 0918−549 的光谱具有较低的信噪比，因此更难以解释，但 4U 0614+09 的一些特征也存在于这些光谱中，尽管有时它们明显较弱。我们得出的结论是，光谱进一步证明了这些 X 射线双星的超紧凑性质以及它们的供体恒星是碳氧白矮星。
We present optical spectra in the range 4600‐8600 ˚ A for three low-mass X-ray binaries which have been suggested to belong to the class of ultra-compact X-ray binaries based on their X-ray spectra. Our spectra show no evidence for hydrogen or helium emission lines, as are seen in classical X-ray binaries. The spectrum of 4U 0614+09 does show emission lines, which we identify with carbon and oxygen lines of C II ,C III ,O II and O III. While the spectra of 4U 1543−624 and 2S 0918−549 have a lower signal-to-noise ratio, and thus are more difficult to interpret, some of the characteristic features of 4U 0614+09 are present in these spectra too, although sometimes they are clearly weaker. We conclude that the optical spectra give further evidence for the ultra-compact nature of these X-ray binaries and for their donor stars being carbon‐oxygen white dwarfs.