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Star formation Process during main accretion phase

Research Project

Project/Area Number 21K03617
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 16010:Astronomy-related
Research InstitutionKyushu University

Principal Investigator

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

Project Period (FY) 2021-04-01 – 2025-03-31
Project Status Completed (Fiscal Year 2024)
Budget Amount *help
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2023: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2022: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2021: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Keywords星形成 / 惑星形成 / ジェット / 磁気流体力学 / 原始惑星系円盤 / 磁気流体 / 原始星 / ダスト / 原始星アウトフロー / アウトフロー / 星周円盤
Outline of Research at the Start

数値シミュレーションを用いて主降着段階の星形成過程を解明する。星が非常に若い段階での星周円盤の成長とダストの振る舞いを調べ、星周円盤中で惑星形成がいつ開始したかを特定する。また、質量降着期のジェットの長時間シミュレーションを行い、原始星への質量降着過程を理解する。その後、シミュレーション結果の観測的可視化を行って星周円盤とジェットのシミュレーション結果と観測結果とを直接比較することによって若い段階の星形成過程を解明する。

Outline of Final Research Achievements

We investigated the evolution of circumstellar disks and the propagation of protostellar outflows during the main accretion phase of star formation. Using three-dimensional non-ideal magnetohydrodynamics simulations, we studied the collapse of a molecular cloud core from the pre-stellar stage through the formation of a protostar and subsequent gas accretion from the envelope. The results show that outflows are driven intermittently due to non-steady gas accretion from the disk onto the protostar. When sufficient mass accumulates in the disk, gravitational instability develops, forming spiral arms that transport angular momentum outward. This angular momentum transport enables enhanced mass infall onto the protostar, which in turn triggers strong outflows. Our study demonstrates that episodic accretion regulated by disk instability plays a key role in driving non-steady outflows during early star formation.

Academic Significance and Societal Importance of the Research Achievements

本研究は、原始星形成期における円盤進化と原始星アウトフローの時間変動を理論的に明らかにした点に学術的意義がある。特に、自己重力不安定に起因する非定常なガス降着と、それに伴うアウトフローの駆動機構を3次元非理想磁気流体シミュレーションにより示した点は重要な成果である。これらの結果は、近年の高分解能観測で得られる非定常現象の解釈に寄与し、惑星系形成や宇宙進化の理解にも貢献する。

Report

(5 results)
  • 2024 Annual Research Report   Final Research Report ( PDF )
  • 2023 Research-status Report
  • 2022 Research-status Report
  • 2021 Research-status Report
  • Research Products

    (28 results)

All 2025 2024 2023 2022 2021 Other

All Int'l Joint Research (1 results) Journal Article (27 results) (of which Int'l Joint Research: 13 results,  Peer Reviewed: 27 results,  Open Access: 17 results)

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

    • Related Report
      2024 Annual Research Report
  • [Journal Article] Complex Structure around a Circumstellar Disk Caused by Interchange Instability2025

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

      The Astrophysical Journal Letters

      Volume: 979 Issue: 2 Pages: L49-L49

    • DOI

      10.3847/2041-8213/adabc5

    • Related Report
      2024 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Tracking Star-forming Cores as Mass Reservoirs in Clustered and Isolated Regions Using Numerical Passive Tracer Particles2025

    • Author(s)
      Nozaki Shingo、Fukushima Hajime、Tokuda Kazuki、Machida Masahiro N.
    • Journal Title

      The Astrophysical Journal

      Volume: 980 Issue: 1 Pages: 101-101

    • DOI

      10.3847/1538-4357/ada602

    • Related Report
      2024 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Observations of spiral and streamer on a candidate proto-brown dwarf2024

    • Author(s)
      Riaz B、Stamatellos D、Machida M N
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 529 Issue: 4 Pages: 3601-3609

    • DOI

      10.1093/mnras/stae724

    • Related Report
      2024 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Cloud Dissipation and Disk Wind in the Late Phase of Star Formation2024

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

      The Astrophysical Journal

      Volume: 970 Issue: 1 Pages: 41-41

    • DOI

      10.3847/1538-4357/ad4997

    • Related Report
      2024 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Dust Polarization of Prestellar and Protostellar Sources in OMC-32024

    • Author(s)
      Liu Yuhua、Takahashi Satoko、Machida Masahiro、Tomisaka Kohji、Girart Josep Miquel、Ho Paul T. P.、Nakanishi Kouichiro、Sato Asako
    • Journal Title

      The Astrophysical Journal

      Volume: 963 Issue: 2 Pages: 104-104

    • DOI

      10.3847/1538-4357/ad182d

    • Related Report
      2023 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Revealing Multiple Nested Molecular Outflows with Rotating Signatures in HH270mms1-A with ALMA2024

    • Author(s)
      Omura Mitsuki、Tokuda Kazuki、Machida Masahiro N.
    • Journal Title

      The Astrophysical Journal

      Volume: 963 Issue: 1 Pages: 72-72

    • DOI

      10.3847/1538-4357/ad19ce

    • Related Report
      2023 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Ring Gap Structure around Class I Protostar WL 172024

    • Author(s)
      Shoshi Ayumu、Harada Naoto、Tokuda Kazuki、Kawasaki Yoshihiro、Yamasaki Hayao、Sato Asako、Omura Mitsuki、Yamaguchi Masayuki、Tachihara Kengo、Machida Masahiro N.
    • Journal Title

      The Astrophysical Journal

      Volume: 961 Issue: 2 Pages: 228-228

    • DOI

      10.3847/1538-4357/ad12b5

    • Related Report
      2023 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Secondary Outflow Driven by the Protostar Ser-emb 15 in Serpens2023

    • Author(s)
      Sato Asako、Tokuda Kazuki、Machida Masahiro N.、Tachihara Kengo、Harada Naoto、Yamasaki Hayao、Hirano Shingo、Onishi Toshikazu、Matsushita Yuko
    • Journal Title

      The Astrophysical Journal

      Volume: 958 Issue: 2 Pages: 102-102

    • DOI

      10.3847/1538-4357/ad0132

    • Related Report
      2023 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] An ALMA-resolved View of 7000 au Protostellar Gas Ring around the Class I Source CrA-IRS 2 as a Possible Sign of Magnetic Flux Advection2023

    • Author(s)
      Tokuda Kazuki、Fukaya Naofumi、Tachihara Kengo、Omura Mitsuki、Harada Naoto、Nozaki Shingo、Shoshi Ayumu、Machida Masahiro N.
    • Journal Title

      The Astrophysical Journal Letters

      Volume: 956 Issue: 1 Pages: L16-L16

    • DOI

      10.3847/2041-8213/acfca9

    • Related Report
      2023 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Impact of turbulence intensity and fragmentation velocity on dust particle size evolution and non-ideal magnetohydrodynamics effects2023

    • Author(s)
      Kawasaki Yoshihiro、Machida Masahiro N
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 522 Issue: 3 Pages: 3679-3692

    • DOI

      10.1093/mnras/stad1241

    • Related Report
      2023 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Magnetic Effects Promote Supermassive Star Formation in Metal-enriched Atomic-cooling Halos2023

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

      The Astrophysical Journal

      Volume: 952 Issue: 1 Pages: 56-56

    • DOI

      10.3847/1538-4357/acda94

    • Related Report
      2023 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] ALMA Fragmented Source Catalog in Orion (FraSCO). I. Outflow Interaction within an Embedded Cluster in OMC-2/FIR 3, FIR 4, and FIR 52023

    • Author(s)
      Sato Asako、Takahashi Satoko、Ishii Shun、Ho Paul T. P.、Machida Masahiro N.、Carpenter John、A. Zapata Luis、Teixeira Paula Stella、Suri sumeyye
    • Journal Title

      The Astrophysical Journal

      Volume: 944 Issue: 1 Pages: 92-92

    • DOI

      10.3847/1538-4357/aca7c9

    • Related Report
      2022 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Crescent-shaped Molecular Outflow from the Intermediate-mass Protostar DK Cha Revealed by ALMA2023

    • Author(s)
      Harada Naoto、Tokuda Kazuki、Yamasaki Hayao、Sato Asako、Omura Mitsuki、Hirano Shingo、Onishi Toshikazu、Tachihara Kengo、Machida Masahiro N.
    • Journal Title

      The Astrophysical Journal

      Volume: 945 Issue: 1 Pages: 63-63

    • DOI

      10.3847/1538-4357/acb930

    • Related Report
      2022 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Environmental effects of star-forming cores on mass accretion rate2023

    • Author(s)
      Nozaki Shingo、Machida Masahiro N
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 519 Issue: 4 Pages: 5017-5030

    • DOI

      10.1093/mnras/stac3819

    • Related Report
      2022 Research-status Report
    • Peer Reviewed
  • [Journal Article] Delivery of Gas onto the Circumplanetary Disk of Giant Planets: Planetary-mass Dependence of the Source Region of Accreting Gas and Mass Accretion Rate2022

    • Author(s)
      Maeda Natsuho、Ohtsuki Keiji、Tanigawa Takayuki、Machida Masahiro N.、Suetsugu Ryo
    • Journal Title

      The Astrophysical Journal

      Volume: 935 Issue: 1 Pages: 56-56

    • DOI

      10.3847/1538-4357/ac7ddf

    • Related Report
      2022 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Exponentially Amplified Magnetic Field Eliminates Disk Fragmentation around Population III Protostars2022

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

      The Astrophysical Journal Letters

      Volume: 935 Issue: 1 Pages: L16-L16

    • DOI

      10.3847/2041-8213/ac85e0

    • Related Report
      2022 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Synthetic Polarization Maps of an Outflow Zone from Magnetohydrodynamic Simulations2022

    • Author(s)
      Bino Gianfranco、Basu Shantanu、Machida Masahiro N.、Tritsis Aris、Sharkawi Mahmoud、Kadam Kundan、Das Indrani
    • Journal Title

      The Astrophysical Journal

      Volume: 936 Issue: 1 Pages: 29-29

    • DOI

      10.3847/1538-4357/ac7c0f

    • Related Report
      2022 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] The First Detection of a Protostellar CO Outflow in the Small Magellanic Cloud with ALMA2022

    • Author(s)
      Tokuda Kazuki、Zahorecz Sarolta、Kunitoshi Yuri、Higashino Kosuke、Tanaka Kei E. I.、Konishi Ayu、Suzuki Taisei、Kitano Naoya、Harada Naoto、Shimonishi Takashi、Neelamkodan Naslim、Fukui Yasuo、Kawamura Akiko、Onishi Toshikazu、Machida Masahiro N.
    • Journal Title

      The Astrophysical Journal Letters

      Volume: 936 Issue: 1 Pages: L6-L6

    • DOI

      10.3847/2041-8213/ac81c1

    • Related Report
      2022 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Dust coagulation and fragmentation in a collapsing cloud core and their influence on non-ideal magnetohydrodynamic effects2022

    • Author(s)
      Kawasaki Yoshihiro、Koga Shunta、Machida Masahiro N
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 515 Issue: 2 Pages: 2072-2087

    • DOI

      10.1093/mnras/stac1919

    • Related Report
      2022 Research-status Report
    • Peer Reviewed
  • [Journal Article] Implementation of dust particles in three-dimensional magnetohydrodynamics simulation: dust dynamics in a collapsing cloud core2022

    • Author(s)
      Koga Shunta、Kawasaki Yoshihiro、Machida Masahiro N
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 515 Issue: 4 Pages: 6073-6092

    • DOI

      10.1093/mnras/stac2115

    • Related Report
      2022 Research-status Report
    • Peer Reviewed
  • [Journal Article] Dust motion and possibility of dust growth in a growing circumstellar disk2022

    • Author(s)
      Koga Shunta、Machida Masahiro N
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 519 Issue: 3 Pages: 3595-3610

    • DOI

      10.1093/mnras/stac3503

    • Related Report
      2022 Research-status Report
    • Peer Reviewed
  • [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 Research-status 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 Research-status 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 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Growth of magnetorotational instability in circumstellar discs around class 0 protostars2021

    • Author(s)
      Kawasaki Yoshihiro、Koga Shunta、Machida Masahiro N
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 504 Issue: 4 Pages: 5588-5611

    • DOI

      10.1093/mnras/stab1224

    • Related Report
      2021 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Super-fast Rotation in the OMC 2/FIR 6b Jet2021

    • Author(s)
      Matsushita Yuko、Takahashi Satoko、Ishii Shun、Tomisaka Kohji、Ho Paul T. P.、Carpenter John M.、Machida Masahiro N.
    • Journal Title

      The Astrophysical Journal

      Volume: 916 Issue: 1 Pages: 23-23

    • DOI

      10.3847/1538-4357/ac069f

    • Related Report
      2021 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Revealing a Centrally Condensed Structure in OMC-3/MMS 3 with ALMA High-resolution Observations2021

    • Author(s)
      Morii Kaho、Takahashi Satoko、Machida Masahiro N.
    • Journal Title

      The Astrophysical Journal

      Volume: 910 Issue: 2 Pages: 148-148

    • DOI

      10.3847/1538-4357/abe61c

    • Related Report
      2021 Research-status Report
    • Peer Reviewed

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Published: 2021-04-28   Modified: 2026-01-16  

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