M-subdwarf Research. II. Atmospheric Parameters and Kinematics
Zhang, Shuo ; Luo, A. -Li ; Comte, Georges ; Wang, Rui ; Li, Yin-Bi ; Du, Bing ; Hou, Wen ; Qin, Li ; Gizis, John ; Chen, Jian-Jun ; Chen, Xiang-Lei ; Lu, Yan ; Song, Yi-Han ; Zhang, Hua-Wei ; Zuo, Fang
We applied the revised M subdwarf classification criteria discussed in Zhang et al. to Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) DR7 and combined the result with the M subdwarf sample from Savcheva et al. to construct a new M subdwarf sample for further study. The atmospheric parameters for each object were derived from fitting to the PHOENIX grid, and the sources with available astrometry and photometry from Gaia DR2 were combined for further analysis. The relationship between the gravity and metallicity was explored according to the locus both in the color-absolute magnitude diagram and the reduced proper motion diagram. Objects that have both the largest gravity and the lowest metallicity are located away from the main-sequence cloud and may be considered as the intrinsic M subdwarfs, which can be classified as luminosity class VI. Another group of objects whose spectra show typical M subdwarf characteristics have lower gravity and relatively moderate metal deficiency and occupy part of the ordinary M dwarf region in both diagrams. The Galactic U, V, W space velocity components and their dispersion show that the local Galactic halo population sampled in the solar neighborhood is represented by objects of high gravity and an inconspicuous bimodal metallicity distribution, with a fraction of prograde orbits. The other M subdwarfs seem to belong in part to the thick disk component, with a significant fraction of thin disk, moderately metal-poor objects intricately mixed with them. However, selection effects, especially the favored anticenter direction of investigation in the LAMOST subsample, as well as contamination by multiplicity and parameter coupling, could play important roles and need to be investigated further.
.. subdwarf-catalog.csv
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Paper Title:
M-subdwarf Research. II. Atmospheric Parameters and Kinematics
The Astrophysical Journal
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Citation Guidelines
Zhang, Shuo et al. 2020. M-subdwarf Research. II. Atmospheric Parameters and Kinematics. Version 1.0. https://doi.org/10.12149/101044
doi = {10.12149/101044},
url = {https://doi.org/10.12149/101044},
author = {Zhang, Shuo},
title = {M-subdwarf Research. II. Atmospheric Parameters and Kinematics},
version = {1.0},
publisher = {Nataional Astronomical Data Center of China},
year= {2020}
Version 1.0 (current)
This DOI represents all versions, and will always resolve to the latest one.