论文标题
Lamost DR4的新水星 - 曼加尼斯明星和候选人
New mercury-manganese stars and candidates from LAMOST DR4
论文作者
论文摘要
目前的工作介绍了我们使用大型天空区域多对象纤维光谱望远镜（Lamost）获得的光谱来识别新的汞山加剂（HGMN/CP3）恒星的努力。使用MKClass代码的修改版本探测了多个HG II和MN II功能的MKClass代码的修改版本，从Lamost DR4中搜索合适的候选物。在视觉上检查了由此产生的332名候选人的光谱。使用Gaia DR2的视差数据和光度法，我们研究了大小，距离太阳的距离以及样品恒星的进化状态。我们还使用不同的光度测量来源搜索可变星。我们提出99个真正的CP3星，19个好CP3星级候选人和7名候选人。我们的样本主要由新的发现，平均包含最微弱的CP3星（峰值分布9.5 <g <13.5 mag）。所有恒星都包含在狭窄的光谱温度类型范围内，从B6到B9.5，与期望和派生的质量估计值非常吻合（大多数对象的2.4 <m（Sun）<4）。我们的样本星为100 MYR至500 MYR旧，覆盖了从零年龄到终端时代主序列的整个年龄范围。它们几乎在主要序列上的分数年龄分布在<80％的主要序列上，而分数年龄在50％至80％之间的物体显然积累。我们发现二进制性对质量和年龄估计的重大影响。发现了八个光度变量，其中大多数与旋转调制一致。我们的工作与最近发表的Apogee CP3星目录一起，显着增加了已知的银河CP3星的样本量，为将来的深入统计研究铺平了道路。
The present work presents our efforts at identifying new mercury-manganese (HgMn/CP3) stars using spectra obtained with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). Suitable candidates were searched for among pre-selected early-type spectra from LAMOST DR4 using a modified version of the MKCLASS code that probes several Hg II and Mn II features. The spectra of the resulting 332 candidates were visually inspected. Using parallax data and photometry from Gaia DR2, we investigated magnitudes, distances from the Sun, and the evolutionary status of our sample stars. We also searched for variable stars using diverse photometric survey sources. We present 99 bona fide CP3 stars, 19 good CP3 star candidates, and seven candidates. Our sample consists of mostly new discoveries and contains, on average, the faintest CP3 stars known (peak distribution 9.5 < G < 13.5 mag). All stars are contained within the narrow spectral temperature-type range from B6 to B9.5, in excellent agreement with the expectations and the derived mass estimates (2.4 < M(Sun) < 4 for most objects). Our sample stars are between 100 Myr and 500 Myr old and cover the whole age range from zero-age to terminal-age main sequence. They are almost homogeneously distributed at fractional ages on the main sequence < 80%, with an apparent accumulation of objects between fractional ages of 50% to 80%. We find a significant impact of binarity on the mass and age estimates. Eight photometric variables were discovered, most of which show monoperiodic variability in agreement with rotational modulation. Together with the recently published catalogue of APOGEE CP3 stars, our work significantly increases the sample size of known Galactic CP3 stars, paving the way for future in-depth statistical studies.
