Stellar wind measurements for Colliding Wind Binaries using X-ray spectra

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K17667
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Astronomy
• Research Institution: Japan Aerospace EXploration Agency
• Principal Investigator: Sugawara Yasuharu 国立研究開発法人宇宙航空研究開発機構, 宇宙科学研究所, 招聘研究員 (80611425)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 宇宙物理 / 大質量星 / X線天文学 / 質量放出 / 恒星進化

Outline of Final Research Achievements

In order to measure "the mass-loss rate of massive star" which is a key of stellar evolution model, X-ray spectroscopic monitoring of elliptical-orbit colliding wind binaries was performed. Since the plasma in the wind-wind collision region emits very strong X-rays, various plasma samples can be obtained by changing the binary separation. By measuring the change in the amount of X-ray absorption, it was possible to calculate mass-loss rate more than twice as accurately as the conventional method. We applied this method to various Colliding wind binaries from 30 days to 10 years of orbital period and succeeded in measuring each mass-loss rate. This study has shown that the new stellar wind measurement method can be applied to the massive binary with various orbital periods.

Free Research Field

X線天文学

Academic Significance and Societal Importance of the Research Achievements

初期宇宙で星は大質量星として誕生すると考えられており、大質量星の進化モデルは初期宇宙の研究にも大きな影響を与える。しかしながら、質量放出率の不定性などにより、大質量星の進化は完全には理解できていない。本研究で得られる不定性の少ない大質量星のパラメータは、大質量星の進化モデルに対して制限を与える可能性があり、銀河の化学的・力学的進化理論へのフィードバックが期待される。