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

  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},
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… 



Fundamental relations for the velocity dispersion of stars in the Milky Way

We explore the fundamental relations governing the radial and vertical velocity dispersions of stars in the Milky Way, from combined studies of complementary surveys including GALAH, LAMOST, APOGEE,

The color represents a median value of υ f . The hand-drawn solid line in (a) reveals where the spiral is. The age range and the number of stars at this age range are marked above each panel