Nearly 30,000 Late-Type Main-Sequence Stars with Stellar Age from LAMOST DR5

Authors

Jiajun Zhang, University of Chinese Academy of Sciences
Terry D. Oswalt, Embry-Riddle Aeronautical UniversityFollow
Jingkun Zhao, University of Chinese Academy of SciencesFollow
Xilong Liang, University of Chinese Academy of SciencesFollow
Xianhao Ye, University of Chinese Academy of SciencesFollow
Gang Zhao, University of Chinese Academy of SciencesFollow

Submitting Campus

Daytona Beach

Department

Physical Sciences

Document Type

Article

Publication/Presentation Date

11-26-2020

Abstract/Description

We construct a sample of nearly 30,000 main-sequence stars with 4500K < Teff < 5000K and stellar ages estimated by the chromospheric activity−age relation. This sample is used to determine the age distribution in the R − Z plane of the Galaxy, where R is the projected Galactocentric distance in the disk midplane and Z is the height above the disk midplane. As |Z| increases, the percentage of old stars becomes larger. It is known that scale-height of Galactic disk increases as R increases, which is called flare. A mild flare from R ∼ 8.0 to 9.0 kpc in stellar age distribution is found. We also find that the velocity dispersion increases with age as confirmed by previous studies. Finally we present spiral-shaped structures in Z − υZ phase space in three stellar age bins. The spiral is clearly seen in the age bin of [0, 1] Gyr, which suggests that a vertical perturbation to the disk probably took place within the last ∼ 1.0 Gyr.

Scholarly Commons Citation

Zhang, J., Oswalt, T. D., Zhao, J., Liang, X., Ye, X., & Zhao, G. (2020). Nearly 30,000 Late-Type Main-Sequence Stars with Stellar Age from LAMOST DR5. , (). Retrieved from https://commons.erau.edu/publication/1493