论文标题
pleiades簇中快速旋转的早期型星的光谱监测
Spectroscopic monitoring of rapidly-rotating early-type stars in the Pleiades cluster
论文作者
论文摘要
由于光谱线的显着旋转宽扩大，pleiades簇中早期型恒星的径向速度一直在挑战。已发表速度的较大散射导致声称许多是光谱二进制物，在某些情况下，已经提出了初步的轨道溶液。为了调查这些主张，我们在此处获得并报告了pleiades地区33个快速旋转B，A和早期F恒星的速度测量值，从而在大多数物体的历史速度的精度上显着提高。除了一两个例外，我们没有确认以前的可变性索赔，并且我们还排除了所有先前发表的轨道溶液中的所有四种，HD 22637，HD 23302，HD 23338和HD 23410。我们确实发现HD 22637是binary，但有不同的时期（71.8天）。 HD 23338也可能是二进制文件，初步的8.7年期也不同于已发布的时期。此外，我们报告了HD 24899的3635天轨道，这是集群中另一个新的光谱二进制。从我们样本中的32个真正的fide成员中，我们确定了5.79 +/- 0.24 km/s的平均径向速度，当排除具有已知视觉伴侣的物体的物体时，或5.52 +/- 0.31 km/s。将这些天文二进制物添加到新的光谱二进制物中，我们发现B中二元分数的下限和37％的恒星。除了速度外，我们还测量了全恒星的V Sin I，范围为69至317 km/s。
Radial-velocities for the early-type stars in the Pleiades cluster have always been challenging to measure because of the significant rotational broadening of the spectral lines. The large scatter in published velocities has led to claims that many are spectroscopic binaries, and in several cases preliminary orbital solutions have been proposed. To investigate these claims, we obtained and report here velocity measurements for 33 rapidly-rotating B, A, and early F stars in the Pleiades region, improving significantly on the precision of the historical velocities for most objects. With one or two exceptions, we do not confirm any of the previous claims of variability, and we also rule out all four of the previously published orbital solutions, for HD 22637, HD 23302, HD 23338, and HD 23410. We do find HD 22637 to be a binary, but with a different period (71.8 days). HD 23338 is likely a binary as well, with a preliminary 8.7 yr period also different from the one published. Additionally, we report a 3635 day orbit for HD 24899, another new spectroscopic binary in the cluster. From the 32 bona fide members in our sample we determine a mean radial velocity for the Pleiades of 5.79 +/- 0.24 km/s, or 5.52 +/- 0.31 km/s when objects with known visual companions are excluded. Adding these astrometric binaries to the new spectroscopic ones, we find a lower limit to the binary fraction among the B and A stars of 37%. In addition to the velocities, we measure v sin i for all stars, ranging between 69 and 317 km/s.
