Hostname: page-component-8448b6f56d-m8qmq Total loading time: 0 Render date: 2024-04-24T07:57:42.952Z Has data issue: false hasContentIssue false
  • English
  • Français

Decomposition of the Galactic Disk: Abundances and Kinematics

Published online by Cambridge University Press:  01 December 2006

Bacham E. Reddy
Bacham E. Reddy*
Affiliation:
Present address: Indian Institute of Astrophysics, Bangalore, India
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

To this contribution we present a brief review of our recent abundance surveys (Reddy et al. 2003; Reddy et al. 2006) of the Milky Way galaxy. Survey focussed on controlled samples of stars selected based on their kinematic properties to belong either thin disk, thick disk or halo components of the Galaxy. Abundance and kinematic results were obtained for about 400 F-, G- and K- dwarfs. Abundances for 22 elements representing different production mechanisms (α-process, p-capture, Fe-peak, s- and r-process) and sites (AGB, SNIa, SNII) were obtained using high quality and high resolution echelle spectra.

Results showed thin and thick disk components are distinct stellar populations with different chemical history. The ratios of α-elements and a few other elements (like Al, V, and Co) are clearly enhanced for stars in the thick disk compared to thin disk stars at given metallicity. Abundance ratios for halo and thick disk stars are very similar. Dispersion in [X/Fe] ratios at given metallicity is comparable to measurement errors inferring lack of cosmic' scatter. Thick disk stars are older (10-13 Gyrs) compared to their counter parts (1-10 Gyrs) in the thin disk. Abundance results for thin and thick disk stars favor the models of hierarchical formation of the galaxy.

Keywords

Milky WayAbundancesKinematicsGalactic diskHaloThick diskThin disk
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 2 , Symposium S241: Stellar Populations as Building Blocks of Galaxies , December 2006 , pp. 209 - 212
Copyright
Copyright © International Astronomical Union 2007

References

Abadi, M. G., Navarro, J. F., Steinmetz, M., & Eke, V. R. 1993, ApJ 597, 21CrossRefGoogle Scholar
Bensby, T., Feltzing, S., Lundström, I., & Ilyin, I. 2005, A&A 433, 185Google Scholar
Brook, C. B., Gibson, B. K., Martel, H., & Kawata, D. 2005, ApJ 630, 298CrossRefGoogle Scholar
Edvardsson, B., Andersen, J., Gustafsson, B., Lambert, D. L., Nissen, P. E., & Tomkin, J. 1993, A&A 275, 101Google Scholar
Eggen, O. J., Lynden-Bell, D., & Sandage, A. R. 1962, ApJ 136, 748CrossRefGoogle Scholar
Feltzing, S., Bensby, T., & Lundström, I. 2003, A&A Letters, 397, 1Google Scholar
Fuhrmann, K 1998, A&A 338, 161Google Scholar
Gratton, R.G., Carretta, E., Matteucii, F., & Sneden, C. 1996, in: Morrison, H. & Sarajedini, A. (eds.), Formation of the Galactic Halo . . . inside and out ASP conf. series. 92 (San Francisco: ASP), P. 307Google Scholar
Gilmore, G., & Reid, N. 1983, MNRAS 202, 1025CrossRefGoogle Scholar
Kobayashi, C., Umeda, H., Nomoto, K., Tominaga, N., Ohkubo, T 2006, ApJ 653, 1145CrossRefGoogle Scholar
Prochaska, J.X., Naumov, S.O., Carney, B.W., McWilliam, A., & Wolfe, A.M. 2000, AJ 120, 251CrossRefGoogle Scholar
Quinn, P. J., Hernquist, L., & Fullagar, D. P. 1993, ApJ 403, 74CrossRefGoogle Scholar
Ramirez, I., Allende Prieto, C., & Lambert, D.L. 2007, Astro-Ph 0701362Google Scholar
Reddy, B.E., Tomkin, J., Lambert, D.L., & AllendePrieto, C Prieto, C 2003, MNRAS 340, 304CrossRefGoogle Scholar
Reddy, Bacham E., Lambert, David L., & AllendePrieto, C Prieto, C 2006, MNRAS 367, 1329CrossRefGoogle Scholar