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An overall picture of EMP stars using the stellar abundances for galactic archaeology (SAGA) database

Published online by Cambridge University Press:  09 March 2010

Takuma Suda ,
Shimako Yamada ,
Yutaka Katsuta ,
Chikako Ishizuka ,
Yutaka Komiya ,
Takanori Nishimura ,
Wako Aoki  and
Masayuki Y. Fujimoto
Takuma Suda
Affiliation:
Astrophysics Group, EPSAM, Keele University, Keele, Staffordshire, ST5 5BG, UK email: suda@astro.keele.ac.uk, chikako@astro.keele.ac.uk
Shimako Yamada
Affiliation:
Dept. of Cosmosciences, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, 060-0810, Japan email: yamada@astro1.sci.hokudai.ac.jp, kat@astro1.sci.hokudai.ac.jp, fujimoto@astro1.sci.hokudai.ac.jp
Yutaka Katsuta
Affiliation:
Dept. of Cosmosciences, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, 060-0810, Japan email: yamada@astro1.sci.hokudai.ac.jp, kat@astro1.sci.hokudai.ac.jp, fujimoto@astro1.sci.hokudai.ac.jp
Chikako Ishizuka
Affiliation:
Astrophysics Group, EPSAM, Keele University, Keele, Staffordshire, ST5 5BG, UK email: suda@astro.keele.ac.uk, chikako@astro.keele.ac.uk
Yutaka Komiya
Affiliation:
National Astronomical Observatory of Japan, 2-1-21, Osawa, Mitaka, Tokyo, 181-8588, Japan email: yutaka.komiya@nao.ac.jp, nishimura.takanori@nao.ac.jp, aoki.wako@nao.ac.jp
Takanori Nishimura
Affiliation:
National Astronomical Observatory of Japan, 2-1-21, Osawa, Mitaka, Tokyo, 181-8588, Japan email: yutaka.komiya@nao.ac.jp, nishimura.takanori@nao.ac.jp, aoki.wako@nao.ac.jp
Wako Aoki
Affiliation:
National Astronomical Observatory of Japan, 2-1-21, Osawa, Mitaka, Tokyo, 181-8588, Japan email: yutaka.komiya@nao.ac.jp, nishimura.takanori@nao.ac.jp, aoki.wako@nao.ac.jp
Masayuki Y. Fujimoto
Affiliation:
Dept. of Cosmosciences, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, 060-0810, Japan email: yamada@astro1.sci.hokudai.ac.jp, kat@astro1.sci.hokudai.ac.jp, fujimoto@astro1.sci.hokudai.ac.jp
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Abstract

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We explore the general characteristics of extremely metal-poor (EMP) stars in the Galaxy using the Stellar Abundances for Galactic Archaeology (SAGA) database (Suda et al. 2008, PASJ, 60, 1159). The overall trend of EMP stars suggests that there are at least two types of extra mixing to change the surface abundances of EMP stars. One is to deplete lithium abundance during the early phase of giant branch and another is to decrease C/N ratio by one order of magnitude during the red giant branch or AGB phase. On the other hand, these mixing processes are different from those suggested in the Galactic globular clusters because of the different relations between O, Na, Mg, and Al abundances.

Keywords

stars: evolutionstars: abundancesstars: Population IIastronomical data bases: miscellaneous
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 5 , Symposium S265: Chemical Abundances in the Universe: Connecting First Stars to Planets , August 2009 , pp. 90 - 93
Copyright
Copyright © International Astronomical Union 2010

References

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