R144 revealed as a double-lined spectroscopic binary
R144 revealed as a double-lined spectroscopic binary
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R144被发现是双线光谱双星
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
D. Gies
中科院分区：
文献类型：
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作者：
H. Sana;T. Boeckel;F. Tramper;L. Ellerbroek;A. D. Koter;A. D. Koter;A. D. Koter;L. Kaper;A. Moffat;O. Schnurr;F. Schneider;D. Gies
R144是位于剑鱼座30区的一颗WN6h恒星。由于它的高亮度和强x射线通量，它被怀疑是双星，但到目前为止还没有确定它的周期性。在这里，我们展示了在ESO甚大望远镜上获得的R144的新x射手多历元光谱。我们检测到所有光谱线的位置和/或形状的变化。我们测量的径向速度变化幅度大于250 km s - 1在N iv和N v线。此外，N - iii线和N - v线的多普勒频移是反相关的，N - iv线在我们的7个历元中有6个呈现双峰分布。因此，我们得出结论，R144是一个双线光谱双星。可能的轨道周期从2个月到6个月不等，尽管如果轨道是高度偏心的，周期可以达到一年。我们估计这些成分的光谱类型分别为WN5-6h和WN6-7h。该系统的高亮度（log Lbol/L⊙≈6.8）表明，目前的总质量含量约在200-300 M⊙之间，这取决于组成部分的演化阶段。这使得R144成为迄今为止发现的质量最大的双星，其出生时的总质量可能高达400 M⊙。在恒星形成和恒星动力学的背景下，我们简要地讨论了距离R136星团核心60 pc的这样一个大质量物体的存在。
R144 is a WN6h star in the 30 Doradus region. It is suspected to be a binary because of its high luminosity and its strong X-ray flux, but no periodicity could be established so far. Here, we present new X-shooter multi-epoch spectroscopy of R144 obtained at the ESO Very Large Telescope. We detect variability in position and/or shape of all the spectral lines. We measure radial velocity variations with an amplitude larger than 250 km s−1 in N iv and N v lines. Furthermore, the N iii and N v line Doppler shifts are anticorrelated and the N iv lines show a double-peaked profile on six of our seven epochs. We thus conclude that R144 is a double-lined spectroscopic binary. Possible orbital periods range from two to six months, although a period up to one year is allowed if the orbit is highly eccentric. We estimate the spectral types of the components to be WN5-6h and WN6-7h, respectively. The high luminosity of the system (log Lbol/L⊙ ≈ 6.8) suggests a present-day total mass content in the range of about 200-300 M⊙, depending on the evolutionary stage of the components. This makes R144 the most massive binary identified so far, with a total mass content at birth possibly as large as 400 M⊙. We briefly discuss the presence of such a massive object, 60 pc away from the R136 cluster core in the context of star formation and stellar dynamics.