astro-ph 2012-11-6

2012-11-5
[astro-ph]
Title: Galactic archaeology: mapping and dating stellar populations with asteroseismology of red-giant stars
Author: A. Miglio (School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
http://arxiv.org/pdf/1211.0146v1.pdf
key points:
a. processes influnence the Galactic evolution
             gas accretion and in-situ SF
             mergers
             local dynamical ( eg. migration and diffraction of stars)
---> which is more important? at what time?
                                   The age of MW. (~ 10 Gyr, 13.6 Gyr), sun (~5Gyr)
b. two cornerstones of Galactic Archaeology:
             stellar distance
             stellar age ( 1.limited to only small sample of field stars; 2. model or empirical relation)
c. Red giants are good candidates for testing chemo-dynamical model of the MK:
            "covering a wide domain in mass, age, metallictiy, evolution stage
---> but then the problem is how to get these parameters (from the stars' surface? )
 d. observations of stellar pulsation come to rescue(Kepler, CoRot): 『asteroseismology』,
oscillation spectra + model --> R，M + mass-metallicty-luminosity relation --> distance
frequency res.~ 0.08 uHz
1. R distribution is similar
2. age(hence M) distribution is different, blue ones expected to be older
 related to the assumed age-dependent vertical scale height of the thin disk
so their observed distribution is in qualitive agreement with the model