分类： 天文学 >> 天文学 提交时间： 2023-02-19
Zhong-Rui Bai
Hao-Tong Zhang
Hai-Long Yuan
Dong-Wei Fan
Bo-Liang He
Ya-Juan Lei
Yi-Qiao Dong
Si-Cheng Yu
Yong-Heng Zhao
Yong Zhang
Yong-Hui Hou
Yao-Quan Chu
摘要： LAMOST Data Release 5, covering $\sim$17,000 $deg^2$ from $-10^{\circ}$ to $80^{\circ}$ in declination, contains 9 millions co-added low resolution spectra of celestial objects, each spectrum combined from repeat exposure of two to tens of times during Oct 2011 to Jun 2017. In this paper, We present the spectra of individual exposures for all the objects in LAMOST Data Release 5. For each spectrum, equivalent width of 60 lines from 11 different elements are calculated with a new method combining the actual line core and fitted line wings. For stars earlier than F type, the Balmer lines are fitted with both emission and absorption profiles once two components are detected. Radial velocity of each individual exposure is measured by minimizing ${\chi}^2$ between the spectrum and its best template. Database for equivalent widths of spectral lines and radial velocities of individual spectra are available online. Radial velocity uncertainties with different stellar type and signal-to-noise ratio are quantified by comparing different exposure of the same objects. We notice that the radial velocity uncertainty depends on the time lag between observations. For stars observed in the same day and with signal-to-noise ratio higher than 20, the radial velocity uncertainty is below 5km/s, and increase to 10km/s for stars observed in different nights.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Jiao Li
Jiang-Dan Li
Yan-Jun Guo
Zhan-Wen Han
Xue-Fei Chen
Chao Liu
Hong-Wei Ge
Deng-Kai Jiang
Li-Fang Li
Bo Zhang
Jia-Ming Liu
Hao Tian
Hao-Tong Zhang
Hai-Long Yuan
Wen-Yuan Cui
Juan-Juan Ren
Jing-Hao Cai
Jian-Rong Shi
摘要： LAMOST-MRS-B is one of the sub-surveys of LAMOST medium-resolution (R~7500) spectroscopic survey. It aims at studying the statistical properties (e.g., binary fraction, orbital period distribution, mass ratio distribution) of binary stars and exotic stars. We intend to observe about 30000 stars (10 mag = 10, respectively. Most of the sources are B-, A-, and F-type stars with 0.6 < [Fe/H] < 0.4 dex. We also obtain 347 identified variable and exotic stars and about 250 stars with [Fe/H] < 1 dex. We measure radial velocities (RVs) by using 892233 spectra of the stars. The uncertainties of RV achieve about 1 km/s and 10 km/s1 for 95% of late- and early-type stars, respectively. The datasets presented in this paper are available at http://www.doi.org/10.57760/sciencedb.j00113.00035.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Jiao Li
Jiang-Dan Li
Yan-Jun Guo
Zhan-Wen Han
Xue-Fei Chen
Chao Liu
Hong-Wei Ge
Deng-Kai Jiang
Li-Fang Li
Bo Zhang
Jia-Ming Liu
Hao Tian
Hao-Tong Zhang
Hai-Long Yuan
Wen-Yuan Cui
Juan-Juan Ren
Jing-Hao Cai
Jian-Rong Shi
摘要： LAMOST-MRS-B is one of the sub-surveys of LAMOST medium-resolution (R~7500) spectroscopic survey. It aims at studying the statistical properties (e.g., binary fraction, orbital period distribution, mass ratio distribution) of binary stars and exotic stars. We intend to observe about 30000 stars (10 mag = 10, respectively. Most of the sources are B-, A-, and F-type stars with 0.6 < [Fe/H] < 0.4 dex. We also obtain 347 identified variable and exotic stars and about 250 stars with [Fe/H] < 1 dex. We measure radial velocities (RVs) by using 892233 spectra of the stars. The uncertainties of RV achieve about 1 km/s and 10 km/s1 for 95% of late- and early-type stars, respectively. The datasets presented in this paper are available at http://www.doi.org/10.57760/sciencedb.j00113.00035.
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