Journal
ASTRONOMY & ASTROPHYSICS
Volume 421, Issue 3, Pages 969-976Publisher
EDP SCIENCES S A
DOI: 10.1051/0004-6361:20035957
Keywords
stars : Hertzsprung-Russell (HR) and C-M diagrams; stars : kinematics; Galaxy : disk; Galaxy : kinematics and dynamics; Galaxy : solar neighbourhood; Galaxy : formation
Categories
Ask authors/readers for more resources
A sample of 229 nearby thick disk stars has been used to investigate the existence of an age-metallicity relation (AMR) in the Galactic thick disk. The results indicate that that there is indeed an age-metallicity relation present in the thick disk. By dividing the stellar sample into sub-groups, separated by 0.1 dex in metallicity, we show that the median age decreases by about 5-7 Gyr when going from [Fe/H]approximate to-0.8 to [Fe/H]approximate to-0.1. Combining our results with our newly published a-element trends for a local sample of thick disk stars that show signatures from supernovae type Ia (SN Ia), we draw the conclusion that the time-scale for the peak of the SN Ia rate is of the order of 3-4 Gyr in the thick disk. The tentative evidence for a thick disk AMR that we present here also has implications for the thick disk formation scenario; star-formation must have been an ongoing process for several billion years. This appears to strengthen the hypothesis that the thick disk originated from a merger event with a companion galaxy that puffed up a pre-existing thin disk.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available