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

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