Lamost Observations in the Kepler Field. Analysis of the Stellar Parameters Measured With Lasp Based on Low-Resolution Spectra*

Abstract

All of the 14 subfields of the Kepler field have been observed at least once with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (lamost, Xinglong Observatory, China) during the 2012-2014 observation seasons. There are 88,628 reduced spectra with SNR g (signal-to-noise ratio in g band) ≥ 6 after the first round (2012-2014) of observations for the lamost-Kepler project (LKproject). By adopting the upgraded version of the lamost Stellar Parameter pipeline (lasp), we have determined the atmospheric parameters (T eff , log g, and [Fe/H]) and heliocentric radial velocity v rad for 51,406 stars with 61,226 spectra.Compared with atmospheric parameters derived from both high-resolution spectroscopy and asteroseismology method for common stars in Huber et al. (2014), an external calibration of lasp atmospheric parameters was made, leading to the determination of external errors for the giants and dwarfs, respectively. Multiple spectroscopic observations for the same objects of the LK-project were used to estimate the internal uncertainties of the atmospheric parameters as a function of SNR g with the unbiased estimation method. The lasp atmospheric parameters were calibrated based on both the external and internal uncertainties for the giants and dwarfs, respectively. A general statistical analysis of the stellar parameters leads to discovery of 106 candidate metal-poor stars, 9 candidate very metal-poor stars, and 18 candidate high-velocity stars. Fitting formulae were obtained segmentally for both the calibrated atmospheric parameters of the LK-project and the KIC parameters with the common stars. The calibrated atmospheric parameters and radial velocities of the LK-project will be useful for studying stars in the Kepler field.

LAMOST Observations in the Kepler Field. II. Database of the Low-resolution Spectra from the Five-year Regular Survey*

“…) will focus on the same topic with a database more than twice the previous spectral library, from 61 226 to 173 971. The number of common stars which have been observed by both Kepler and LAMOST is 76 283, a number larger than twice the data size of Ren et al (2016). In addition, the previous spectra have been re-analyzed with the updated version of the LASP code, v2.9.7, where the determination of uncertainty of radial velocity is improved significantly.…”

“…In addition, the previous spectra have been re-analyzed with the updated version of the LASP code, v2.9.7, where the determination of uncertainty of radial velocity is improved significantly. The new calibration examines the reliability of the previous results provided by Ren et al (2016), to establish more generic calibration formulae.…”

The 13th Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey Mapping Nearby Galaxies at Apache Point Observatory

“…Data 130 Release 3 includes 5.75 million spectra and stellar parameters for >3 million stars. LAMOST has an ideal view of the field observed for four years by the Kepler satellite, and several groups have used the ∼50,000 stars observed in the Kepler field to characterize its stellar populations (e.g., Dong et al 2014;Frasca et al 2016;Ren et al 2016;Chang et al 2017;Dong et al 2017). Other work based on LAMOST spectra includes measurements of stellar activity (e.g., Fang et al 2016) and identification of important subclasses of objects from ultra-metal-poor stars (e.g., and metalliclined Am stars (e.g., Hou et al 2015).…”

The binarity of Galactic dwarf stars along with effective temperature and metallicity

“…Gao et al (2015 found that the standard deviations of 110 K, 0.11 dex and 4.91 km s −1 , for T eff , [Fe/H] and RV. According to the work of Ren et al (2016), LAMOST's T eff and [Fe/H] have the deviation of about 100 K and 0.1 dex in Kepler field, respectively. The pipeline and these independent validations confirm the accuracy of T eff and [Fe/H] for dwarfs, which is matching the coverage of parameters in our sample.…”