Young Stellar Object Jets Magnetocentrifugally Driven by Reconnecting Atmospheric Avalanche Accretion Streams above Inner Circumstellar Disks
Fast, collimated jets are ubiquitous features of young stellar objects. They are generally thought to be powered by disk accretion, but the details are debated. Through 2D (axisymmetric) MHD simulations, we find that a fast (>100 km s ^−1 ) collimated bipolar jet is continuously driven along the...
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2024-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad927b |
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| author | Yisheng Tu Zhi-Yun Li Zhaohuan Zhu Xiao Hu Chun-Yen Hsu |
| author_facet | Yisheng Tu Zhi-Yun Li Zhaohuan Zhu Xiao Hu Chun-Yen Hsu |
| author_sort | Yisheng Tu |
| collection | DOAJ |
| description | Fast, collimated jets are ubiquitous features of young stellar objects. They are generally thought to be powered by disk accretion, but the details are debated. Through 2D (axisymmetric) MHD simulations, we find that a fast (>100 km s ^−1 ) collimated bipolar jet is continuously driven along the north and south poles of a circumstellar disk that is initially magnetized by a large-scale open poloidal field and contains a thermally ionized inner magnetically active zone surrounded by a dead zone. The fast jet is primarily driven magnetocentrifugally by the release of the gravitational binding energy of the so-called “avalanche accretion streams” near the boundary of an evacuated poloidal field dominated polar region and a thick disk atmosphere raised by a toroidal magnetic field. Specifically, the fast outflow is driven along the upper (open) branch of the highly pinched poloidal field lines threading the (strongly magnetically braked) accretion streams, where the density is relatively low so that the lightly loaded material can be accelerated magnetocentrifugally along the open field line to a high speed. The highly pinched poloidal magnetic fields threading the avalanche accretion streams tend to reconnect, enabling mass to accrete to the center without dragging along the poloidal magnetic flux with it. The reconnection provides a potential heating source for producing chondrules and calcium- and aluminum-rich inclusions. |
| format | Article |
| id | doaj-art-9decbf698c0e4d938d47f0db0cd82528 |
| institution | OA Journals |
| issn | 1538-4357 |
| language | English |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-9decbf698c0e4d938d47f0db0cd825282025-08-20T01:57:35ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-0197818410.3847/1538-4357/ad927bYoung Stellar Object Jets Magnetocentrifugally Driven by Reconnecting Atmospheric Avalanche Accretion Streams above Inner Circumstellar DisksYisheng Tu0https://orcid.org/0000-0003-2929-1502Zhi-Yun Li1https://orcid.org/0000-0002-7402-6487Zhaohuan Zhu2https://orcid.org/0000-0003-3616-6822Xiao Hu3https://orcid.org/0000-0003-3201-4549Chun-Yen Hsu4https://orcid.org/0000-0003-3567-0680Astronomy Department, University of Virginia , Charlottesville, VA 22904, USAAstronomy Department, University of Virginia , Charlottesville, VA 22904, USADepartment of Physics and Astronomy, University of Nevada , Las Vegas, NV 89154-4002, USAAstronomy Department, University of Virginia , Charlottesville, VA 22904, USA; Department of Astronomy, University of Florida , Gainesville, FL 32608, USAAstronomy Department, University of Virginia , Charlottesville, VA 22904, USAFast, collimated jets are ubiquitous features of young stellar objects. They are generally thought to be powered by disk accretion, but the details are debated. Through 2D (axisymmetric) MHD simulations, we find that a fast (>100 km s ^−1 ) collimated bipolar jet is continuously driven along the north and south poles of a circumstellar disk that is initially magnetized by a large-scale open poloidal field and contains a thermally ionized inner magnetically active zone surrounded by a dead zone. The fast jet is primarily driven magnetocentrifugally by the release of the gravitational binding energy of the so-called “avalanche accretion streams” near the boundary of an evacuated poloidal field dominated polar region and a thick disk atmosphere raised by a toroidal magnetic field. Specifically, the fast outflow is driven along the upper (open) branch of the highly pinched poloidal field lines threading the (strongly magnetically braked) accretion streams, where the density is relatively low so that the lightly loaded material can be accelerated magnetocentrifugally along the open field line to a high speed. The highly pinched poloidal magnetic fields threading the avalanche accretion streams tend to reconnect, enabling mass to accrete to the center without dragging along the poloidal magnetic flux with it. The reconnection provides a potential heating source for producing chondrules and calcium- and aluminum-rich inclusions.https://doi.org/10.3847/1538-4357/ad927bJetsAccretionCircumstellar disksYoung stellar objects |
| spellingShingle | Yisheng Tu Zhi-Yun Li Zhaohuan Zhu Xiao Hu Chun-Yen Hsu Young Stellar Object Jets Magnetocentrifugally Driven by Reconnecting Atmospheric Avalanche Accretion Streams above Inner Circumstellar Disks The Astrophysical Journal Jets Accretion Circumstellar disks Young stellar objects |
| title | Young Stellar Object Jets Magnetocentrifugally Driven by Reconnecting Atmospheric Avalanche Accretion Streams above Inner Circumstellar Disks |
| title_full | Young Stellar Object Jets Magnetocentrifugally Driven by Reconnecting Atmospheric Avalanche Accretion Streams above Inner Circumstellar Disks |
| title_fullStr | Young Stellar Object Jets Magnetocentrifugally Driven by Reconnecting Atmospheric Avalanche Accretion Streams above Inner Circumstellar Disks |
| title_full_unstemmed | Young Stellar Object Jets Magnetocentrifugally Driven by Reconnecting Atmospheric Avalanche Accretion Streams above Inner Circumstellar Disks |
| title_short | Young Stellar Object Jets Magnetocentrifugally Driven by Reconnecting Atmospheric Avalanche Accretion Streams above Inner Circumstellar Disks |
| title_sort | young stellar object jets magnetocentrifugally driven by reconnecting atmospheric avalanche accretion streams above inner circumstellar disks |
| topic | Jets Accretion Circumstellar disks Young stellar objects |
| url | https://doi.org/10.3847/1538-4357/ad927b |
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