Magnetic Field Amplification during Stellar Collisions between Low-mass Stars
Blue straggler stars in stellar clusters appear younger and bluer than other cluster members, offering a unique opportunity to understand the stellar dynamics and populations within their hosts. In the collisional formation scenario, excessive angular momentum in the collision product poses a challe...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/2041-8213/adaf94 |
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| Summary: | Blue straggler stars in stellar clusters appear younger and bluer than other cluster members, offering a unique opportunity to understand the stellar dynamics and populations within their hosts. In the collisional formation scenario, excessive angular momentum in the collision product poses a challenge, as the consequent significant mass loss during transition to a stable state leads to a star with too low of a mass to be a blue straggler, unless it spins down efficiently. While many proposed spin-down mechanisms require magnetic fields, the existence or strength of these magnetic fields has not been confirmed. Here, we present 3D moving-mesh magnetohydrodynamical simulations of collisions between low-mass main-sequence stars and investigate magnetic field amplification. Magnetic field energy is amplified during collisions by a factor of 10 ^8 –10 ^10 , resulting in the magnetic field strength of 10 ^7 –10 ^8 G at the core of the collision product, independent of collision parameters. The surface magnetic field strengths increase up to 10–10 ^4 G. In addition, a distinctly flattened, rotating gas structure appears around the collision products in off-axis collisions, suggesting potential disk formation. These findings indicate that magnetic braking and disk locking could facilitate spin-down, enabling the formation of blue straggler stars. |
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| ISSN: | 2041-8205 |