标题： LAMOST光谱巡天OB星目录 显示英文标题

标题： A Catalogue of OB Stars from LAMOST Spectroscopic Survey

摘要： 我们展示了来自LAMOST DR5数据集的16032颗恒星的22901条OB型光谱。 首先，从光谱线指数空间的分布中选出更大样本的OB候选者。 然后通过人工检查识别出全部22901条OB光谱。 基于子样本验证，我们发现对于光谱型早于B7的恒星，OB光谱的完整性达到约$89\pm22$%，而对于B8–B9型恒星，大约有$57\pm16$%被识别出来。 晚B型恒星的较小完整性是由于难以将其与A0–A1型恒星区分开来。 使用软件包MKCLASS确定了OB样本的子类别。 通过对646个子样本的仔细验证，我们发现MKCLASS可以为大多数OB恒星提供相当可靠的子类型和光度等级。 光谱子类型的不确定性约为1个子类型，光度等级的不确定性约为1级。 然而，约40%的OB恒星未能被MKCLASS分配到任何类别，少数光谱被显著误分类。 这可能是因为MKCLASS的模板光谱是从太阳邻域附近的恒星中选择的，而本研究中的OB恒星大多位于外盘且可能具有较低的金属丰度。 OB恒星的旋转也可能导致分类错误。 此外，我们发现位于银纬大于20$^\circ$的OB恒星的光谱和光度等级与位于银纬小于20$^\circ$的恒星有显著差异，这可能是观测选择效应的结果，也可能是暗示高银纬OB恒星具有不同的起源。 显示英文摘要

摘要： We present 22\,901 OB spectra of 16\,032 stars identified from LAMOST DR5 dataset. A larger sample of OB candidates are firstly selected from the distributions in the spectral line indices space. Then all 22\,901 OB spectra are identified by manual inspection. Based on a sub-sample validation, we find that the completeness of the OB spectra reaches about $89\pm22$\% for the stars with spectral type earlier than B7, while around $57\pm16$\% B8--B9 stars are identified. The smaller completeness for late B stars is lead to the difficulty to discriminate them from A0--A1 type stars. The sub-classes of the OB samples are determined using the software package MKCLASS. With a careful validation using 646 sub-samples, we find that MKCLASS can give fairly reliable sub-types and luminosity class for most of the OB stars. The uncertainty of the spectral sub-type is around 1 sub-type and the uncertainty of the luminosity class is around 1 level. However, about 40\% of the OB stars are failed to be assigned to any class by MKCLASS and a few spectra are significantly misclassified by MKCLASS. This is likely because that the template spectra of MKCLASS are selected from nearby stars in the solar neighborhood, while the OB stars in this work are mostly located in the outer disk and may have lower metallicity. The rotation of the OB stars may also be responsible for the mis-classifications. Moreover, we find that the spectral and luminosity classes of the OB stars located in the Galactic latitude larger than 20$^\circ$ are substantially different with those located in latitude smaller than 20$^\circ$, which may either due to the observational selection effect or hint a different origin of the high Galactic latitude OB stars.