• DOI:10.3847/1538-4357/abce5b
• Corpus ID: 227162209

Nearly 30,000 Late-type Main-sequence Stars with Stellar Age from LAMOST DR5

@article{Zhang2020Nearly3L,
  title={Nearly 30,000 Late-type Main-sequence Stars with Stellar Age from LAMOST DR5},
  author={Jiajun Zhang and Jingkun Zhao and Terry D. Oswalt and Xilong Liang and Xianhao Ye and Gang Zhao},
  journal={The Astrophysical Journal},
  year={2020},
  volume={908}
}

• Jiajun Zhang, Jingkun Zhao, +3 authors Gang Zhao
• Published 25 November 2020
• Physics, Geology
• The Astrophysical Journal

We construct a sample of nearly 30,000 main-sequence stars with 4500 K < Teff < 5000 K 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 a 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.