Evolution timescale of young stars

2018 Fiscal Year Final Research Report

• Project/Area Number: 26870507
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Solid earth and planetary physics; Astronomy
• Research Institution: National Astronomical Observatory of Japan (2016-2018); University of Hyogo (2014-2015)
• Principal Investigator: Takagi Yuhei 国立天文台, ハワイ観測所, RCUH職員 (80648973)
• Research Collaborator: Itoh Yoichi ; Oasa Yumiko ; Honda Satoshi ; Arai Akira
• Project Period (FY): 2014-04-01 – 2019-03-31
• Keywords: 星・惑星形成

Outline of Final Research Achievements

Age determination of young stars is crucial for the understanding of the evolution of young stars and protoplanetary disks. An original age determination method based on high-resolution spectroscopy was used to discuss the evolution timescale of protoplanetary disks, and I found that the disk lifetime depends on the nature of the star-forming regions.
Spectroscopic monitoring observations of FU Ori type star V960 Mon was also conducted to understand the evolution of protoplanetary disks during the FU Ori outburst. The variation in obtained spectra shows the change of effective temperature and the surface gravity of the disk during the outburst, indicating the physical evolution of the protoplanetary disk.

Free Research Field

天文学

Academic Significance and Societal Importance of the Research Achievements

星は分子雲と呼ばれるガスの塊から誕生し、生まれた星の周りを取り囲むように原始惑星系円盤で惑星が生まれる。太陽系も同様の過程で生まれたが、その詳しい様子はまだ未解明な点が多い。本研究では、若い星の年齢を分光観測による新しい手法で求め、原始惑星系円盤が進化するために必要な時間を調べた結果、星形成領域によりその時間が異なることがわかった。また、FU Ori型星と呼ばれる、原始惑星系円盤から中心星に向かってガスが大量に流れ込み増光する天体を3年に渡って分光観測を行った結果、増光中の円盤の進化の様子を捉えることに成功した。