• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to previous page

Understanding the accretion phase of star formation

Research Project

Project/Area Number 17K05387
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Research Field Astronomy
Research InstitutionKyushu University

Principal Investigator

Machida Masahiro  九州大学, 理学研究院, 准教授 (10402786)

Project Period (FY) 2017-04-01 – 2022-03-31
Project Status Completed (Fiscal Year 2021)
Budget Amount *help
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2020: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2017: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Keywords星形成 / 惑星形成 / 磁気流体力学 / 原始星ジェット / 原始惑星系円盤 / 弱電離プラズマ / 磁気流体 / 双極拡散 / 自己重力 / 星間物質 / 分子雲 / 分子雲コア / ジェット / 大質量星 / アウトフロー / 星周円盤 / 原始星 / 降着円盤 / 理論天文学 / 宇宙物理
Outline of Final Research Achievements

Using numerical simulations, the growth of circumstellar disk and jet driving mechanism in the main accretion phase were unveiled. The size growth of the circumstellar disk is suppressed due to magnetic braking outside the disk. However, since the gas accretion onto the disk steadily occurs, the disk becomes gravitationally unstable with time. Then, the disk mass suddenly falls onto the protostar with non-axisymmetric gravitational torque. Then, the disk becomes stable against the self-gravity of the disk. In addition, a part of the falling gas is ejected from the central region as the protostellar jet. This study have shown that the mass accretion onto the protostar and mass ejection by the jet episodically occur in the main accretion phase.

Academic Significance and Societal Importance of the Research Achievements

星は宇宙の最も基本的な構成要素である。そのため、星の形成過程を理解することは宇宙の進化を解明することにつながる。近年の観測から、星周円盤中で惑星が形成していることや、原始星近傍から高速のジェットが駆動していることが分かった。
この研究では星形成の大規模数値シミュ―レーションを実行し、惑星形成の母体となる星周円盤の形成過程と星形成ジェットの駆動機構を解明した。この研究をさらに発展させることにより地球のような惑星がどのようにして誕生するのかを解明することが出来る。

Report

(6 results)
  • 2021 Annual Research Report   Final Research Report ( PDF )
  • 2020 Research-status Report
  • 2019 Research-status Report
  • 2018 Research-status Report
  • 2017 Research-status Report
  • Research Products

    (19 results)

All 2021 2020 2019 2018 2017 Other

All Int'l Joint Research (1 results) Journal Article (15 results) (of which Int'l Joint Research: 3 results,  Peer Reviewed: 15 results,  Open Access: 4 results) Presentation (3 results)

  • [Int'l Joint Research] Western University(カナダ)

    • Related Report
      2019 Research-status Report
  • [Journal Article] Impact of magnetic braking on high-mass close binary formation2021

    • Author(s)
      Harada Naoto、Hirano Shingo、Machida Masahiro N、Hosokawa Takashi
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 508 Issue: 3 Pages: 3730-3747

    • DOI

      10.1093/mnras/stab2780

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Can high-velocity protostellar jets help to drive low-velocity outflow?2021

    • Author(s)
      Machida Masahiro N
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 508 Issue: 3 Pages: 3208-3225

    • DOI

      10.1093/mnras/stab2626

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Supermassive Star Formation in Magnetized Atomic-cooling Gas Clouds: Enhanced Accretion, Intermittent Fragmentation, and Continuous Mergers2021

    • Author(s)
      Hirano Shingo、Machida Masahiro N.、Basu Shantanu
    • Journal Title

      The Astrophysical Journal

      Volume: 917 Issue: 1 Pages: 34-34

    • DOI

      10.3847/1538-4357/ac0913

    • Related Report
      2021 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Different modes of star formation - II. Gas accretion phase of initially subcritical star-forming clouds2020

    • Author(s)
      Machida, Masahiro N.; Basu, Shantanu
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 494 Issue: 1 Pages: 827-845

    • DOI

      10.1093/mnras/staa672

    • Related Report
      2020 Research-status Report 2019 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Failed and delayed protostellar outflows with high-mass accretion rates2020

    • Author(s)
      Machida Masahiro N、Hosokawa Takashi
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 499 Issue: 3 Pages: 4490-4514

    • DOI

      10.1093/mnras/staa3139

    • Related Report
      2020 Research-status Report
    • Peer Reviewed
  • [Journal Article] Twin Jets and Close Binary Formation2020

    • Author(s)
      Saiki Yu、Machida Masahiro N.
    • Journal Title

      The Astrophysical Journal

      Volume: 897 Issue: 2 Pages: L22-L22

    • DOI

      10.3847/2041-8213/ab9d86

    • Related Report
      2020 Research-status Report
    • Peer Reviewed
  • [Journal Article] Early Evolution of Disk, Outflow, and Magnetic Field of Young Stellar Objects: Impact of Dust Model2020

    • Author(s)
      Tsukamoto Y.、Machida M. N.、Susa H.、Nomura H.、Inutsuka S.
    • Journal Title

      The Astrophysical Journal

      Volume: 896 Issue: 2 Pages: 158-158

    • DOI

      10.3847/1538-4357/ab93d0

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Origin of misalignments: protostellar jet, outflow, circumstellar disc, and magnetic field2019

    • Author(s)
      Hirano, Shingo; Machida, Masahiro N.
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 485 Issue: 4 Pages: 4667-4674

    • DOI

      10.1093/mnras/stz740

    • Related Report
      2018 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Dependence of Hall coefficient on grain size and cosmic ray rate and implication for circumstellar disc formation2019

    • Author(s)
      Koga, Shunta; Tsukamoto, Yusuke; Okuzumi, Satoshi; Machida, Masahiro N.
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 484 Issue: 2 Pages: 2119-2136

    • DOI

      10.1093/mnras/sty3524

    • Related Report
      2018 Research-status Report
    • Peer Reviewed
  • [Journal Article] ALMA High Angular Resolution Polarization Study: An Extremely Young Class 0 Source, OMC-3/MMS 62019

    • Author(s)
      Takahashi, Satoko; Machida, Masahiro N.; Tomisaka, Kohji; Ho, Paul T. P.; Fomalont, Edward B.; Nakanishi, Kouichiro; Girart, Josep Miquel
    • Journal Title

      The Astrophysical Journal

      Volume: 872 Issue: 1 Pages: 15-15

    • DOI

      10.3847/1538-4357/aaf6ed

    • Related Report
      2018 Research-status Report
    • Peer Reviewed
  • [Journal Article] A Very Compact Extremely High Velocity Flow toward MMS 5/OMC-3 Revealed with ALMA2019

    • Author(s)
      Matsushita, Yuko; Takahashi, Satoko; Machida, Masahiro N.; Tomisaka, Kohji
    • Journal Title

      The Astrophysical Journal

      Volume: 871 Issue: 2 Pages: 12-12

    • DOI

      10.3847/1538-4357/aaf1b6

    • Related Report
      2018 Research-status Report
    • Peer Reviewed
  • [Journal Article] Evolution of magnetic fields in collapsing star-forming clouds under different environments2018

    • Author(s)
      Higuchi, Koki; Machida, Masahiro N.; Susa, Hajime
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 475 Issue: 3 Pages: 3331-3347

    • DOI

      10.1093/mnras/sty046

    • Related Report
      2017 Research-status Report
    • Peer Reviewed
  • [Journal Article] Massive outflows driven by magnetic effects - II. Comparison with observations2018

    • Author(s)
      Matsushita, Yuko; Sakurai, Yuya; Hosokawa, Takashi; Machida, Masahiro N.
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 475 Issue: 1 Pages: 391-403

    • DOI

      10.1093/mnras/stx3070

    • Related Report
      2017 Research-status Report
    • Peer Reviewed
  • [Journal Article] Different modes of star formation: gravitational collapse of magnetically subcritical cloud2018

    • Author(s)
      Machida, Masahiro N.; Higuchi, Koki; Okuzumi, Satoshi
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 473 Issue: 3 Pages: 3080-3094

    • DOI

      10.1093/mnras/stx2589

    • Related Report
      2017 Research-status Report
    • Peer Reviewed
  • [Journal Article] Massive outflows driven by magnetic effects in star-forming clouds with high mass accretion rates2018

    • Author(s)
      Matsushita, Yuko; Machida, Masahiro N.; Sakurai, Yuya; Hosokawa, Takashi
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 475 Issue: 1 Pages: 1026-1049

    • DOI

      10.1093/mnras/stx893

    • Related Report
      2017 Research-status Report
    • Peer Reviewed
  • [Presentation] Class 0天体MMS5から駆動するアウトフローとジェットの軸のずれ2018

    • Author(s)
      松下祐子, 高橋智子, 町田正博, 富阪幸治
    • Organizer
      日本天文学会春季年会
    • Related Report
      2017 Research-status Report
  • [Presentation] 中間質量星形成領域OMC-3 MMS5に付随するEHVアウトフロー2017

    • Author(s)
      松下祐子, 高橋智子, 町田正博, 富阪幸治
    • Organizer
      日本天文学会秋季年会
    • Related Report
      2017 Research-status Report
  • [Presentation] 低金属量環境における星形成過程2017

    • Author(s)
      樋口公紀, 町田正博, 須佐元
    • Organizer
      日本天文学会秋季年会
    • Related Report
      2017 Research-status Report

URL: 

Published: 2017-04-28   Modified: 2023-01-30  

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi