Open AccessHipparcos and the age of the Galactic disc
Author(s) -
Jimenez Raul,
Flynn Chris,
Kotoneva Eira
Publication year - 1998
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1998.01787.x
Subject(s) - physics , astrophysics , stars , diagram , hertzsprung–russell diagram , magnitude (astronomy) , red clump , astronomy , red giant branch , giant star , envelope (radar) , luminosity function , horizontal branch , abundance (ecology) , main sequence , red giant , luminosity , stellar evolution , globular cluster , metallicity , galaxy , statistics , telecommunications , radar , mathematics , fishery , computer science , biology
We use the Hipparcos colour–magnitude diagram of field stars with Tycho colours to make a new minimum age estimate for the Galactic disc. The method is based on fits to the red envelope of subgiants in the Hipparcos colour–magnitude diagram with synthetic isochrones covering the range of disc metal abundance. The colours and luminosities of the isochrones as a function of abundance are checked using new techniques involving ‘red‐clump’ stars in the giant branch region and on the main sequence using G and K dwarfs. We derive a minimum disc age of 8 Gyr, in good agreement with other methods.