2001 Fiscal Year Final Research Report Summary
Observational study on the evolution of AGB stars and their mass-loss
| Project/Area Number |
12640234
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Astronomy
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| Research Institution | The University of Tokyo |
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Principal Investigator |
TANABE Toshihiko The University of Tokyo, Graduate School of Science, Research associate, 大学院・理学系研究科, 助手 (90179812)
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| Co-Investigator(Kenkyū-buntansha) |
ONAKA Takashi The University of Tokyo, Graduate School of Science, Professor, 大学院・理学系研究科, 教授 (30143358)
NAKADA Yoshikazu The University of Tokyo, Graduate School of Science, Professor, 大学院・理学系研究科, 教授 (80011740)
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| Project Period (FY) |
2000 – 2001
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| Keywords | stellar evolution / stars - late stages / stars - AGB / mass-loss / cool stars / long period variables / circumstcllar dust / Magellanic Clouds |
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| Research Abstract |
It is well known that globular clusters (GCs) associated with the Magellanic Clouds (MCs) are an ideal test field for the theory of stellar evolution because fundamental parameters of a star such as the mass, luminosity, metallicity, etc. can be estimated. We performed repeated observations of GCs in the MCs at South African Astronomical Observatory (SAAO) with a newly built 1.4 m telescope, IRSF and a near-infrared camera, SIRIUS and obtained the following results.
1. We found that stars in the upper AGB all show variabilities and their periods and ampitudes tend to increase along AGB. At the tip of the AGB, stars turn to be Ions period variables, possibly Mira types.
2. The mass-loss does not seem to occur along AGB but occur in a some special phase, probably in a very late phase.
Although we found many variable stars, we could not detect short-period and possibly low amplitude variables because our observational chances were not dense. When the variability appears and how it evolves along AGB and the relationship between the luminosity and period along AGB still remains a future work.
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