LAMOST Time-Domain Survey: First Results of four $K$2 plates. (arXiv:2109.03149v1 [astro-ph.SR])

LAMOST Time-Domain Survey: First Results of four $K$2 plates. (arXiv:2109.03149v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Wang_S/0/1/0/all/0/1">Song Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_H/0/1/0/all/0/1">Haotong Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bai_Z/0/1/0/all/0/1">Zhongrui Bai</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yuan_H/0/1/0/all/0/1">Hailong Yuan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Xiang_M/0/1/0/all/0/1">Maosheng Xiang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_B/0/1/0/all/0/1">Bo Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hou_W/0/1/0/all/0/1">Wen Hou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zuo_F/0/1/0/all/0/1">Fang Zuo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Du_B/0/1/0/all/0/1">Bing Du</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_T/0/1/0/all/0/1">Tanda Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_F/0/1/0/all/0/1">Fan Yang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cui_K/0/1/0/all/0/1">Kaiming Cui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_Y/0/1/0/all/0/1">Yilun Wang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_J/0/1/0/all/0/1">Jiao Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kovalev_M/0/1/0/all/0/1">Mikhail Kovalev</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_C/0/1/0/all/0/1">Chunqian Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tian_H/0/1/0/all/0/1">Hao Tian</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zong_W/0/1/0/all/0/1">Weikai Zong</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Han_H/0/1/0/all/0/1">Henggeng Han</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_C/0/1/0/all/0/1">Chao Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Luo_A/0/1/0/all/0/1">A-Li Luo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shi_J/0/1/0/all/0/1">Jianrong Shi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fu_J/0/1/0/all/0/1">Jian-Ning Fu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bi_S/0/1/0/all/0/1">Shaolan Bi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Han_Z/0/1/0/all/0/1">Zhanwen Han</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_J/0/1/0/all/0/1">Jifeng Liu</a>

From Oct. 2019 to Apr. 2020, LAMOST performs a time-domain spectroscopic
survey of four $K$2 plates with both low- and med-resolution observations. The
low-resolution spectroscopic survey gains 282 exposures ($approx$46.6 hours)
over 25 nights, yielding a total of about 767,000 spectra, and the
med-resolution survey takes 177 exposures ($approx$49.1 hours) over 27 nights,
collecting about 478,000 spectra. More than 70%/50% of
low-resolution/med-resolution spectra have signal-to-noise ratio higher than
10. We determine stellar parameters (e.g., $T_{rm eff}$, log$g$, [Fe/H]) and
radial velocity (RV) with different methods, including LASP, DD-Payne, and
SLAM. In general, these parameter estimations from different methods show good
agreement, and the stellar parameter values are consistent with those of
APOGEE. We use the $Gaia$ DR2 RV data to calculate a median RV zero point
(RVZP) for each spectrograph exposure by exposure, and the RVZP-corrected RVs
agree well with the APOGEE data. The stellar evolutionary and spectroscopic
masses are estimated based on the stellar parameters, multi-band magnitudes,
distances and extinction values. Finally, we construct a binary catalog
including about 2700 candidates by analyzing their light curves, fitting the RV
data, calculating the binarity parameters from med-resolution spectra, and
cross-matching the spatially resolved binary catalog from $Gaia$ EDR3. The
LAMOST TD survey is expected to get breakthrough in various scientific topics,
such as binary system, stellar activity, and stellar pulsation, etc.

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