Complex Structure around a Circumstellar Disk Caused by Interchange Instability

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Auteurs principaux: Machida, Masahiro N., Basu, Shantanu
Format: Preprint
Publié: 2025
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author Machida, Masahiro N.
Basu, Shantanu
author_facet Machida, Masahiro N.
Basu, Shantanu
contents We perform a three-dimensional nonideal magnetohydrodynamic simulation of a strongly magnetized cloud core and investigate the complex structure caused by the interchange instability. This is the first simulation that does not use a central sink cell and calculates the long term ($> 10^4$ yr) evolution even as the disk and outflow formation occur. The magnetic field dissipates inside the disk, and magnetic flux accumulates around the edge of the disk, leading to the occurrence of interchange instability. During the main accretion phase, the interchange instability occurs recurrently, disturbing the circumstellar region and forming ring, arc, and cavity structures. These are consistent with recent high-resolution observations of circumstellar regions around young protostars. The structures extend to $>1,000$ au and persist for at least 30,000 yr after protostar formation, demonstrating the dynamic removal process of magnetic flux during star formation. We find that the disk continues to grow even as interchange instability occurs, by accretion through channels between the outgoing cavities. The outflow is initially weak, but becomes strong after $\sim 10^3$ yr.
format Preprint
id arxiv_https___arxiv_org_abs_2501_08701
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Complex Structure around a Circumstellar Disk Caused by Interchange Instability
Machida, Masahiro N.
Basu, Shantanu
Solar and Stellar Astrophysics
Astrophysics of Galaxies
We perform a three-dimensional nonideal magnetohydrodynamic simulation of a strongly magnetized cloud core and investigate the complex structure caused by the interchange instability. This is the first simulation that does not use a central sink cell and calculates the long term ($> 10^4$ yr) evolution even as the disk and outflow formation occur. The magnetic field dissipates inside the disk, and magnetic flux accumulates around the edge of the disk, leading to the occurrence of interchange instability. During the main accretion phase, the interchange instability occurs recurrently, disturbing the circumstellar region and forming ring, arc, and cavity structures. These are consistent with recent high-resolution observations of circumstellar regions around young protostars. The structures extend to $>1,000$ au and persist for at least 30,000 yr after protostar formation, demonstrating the dynamic removal process of magnetic flux during star formation. We find that the disk continues to grow even as interchange instability occurs, by accretion through channels between the outgoing cavities. The outflow is initially weak, but becomes strong after $\sim 10^3$ yr.
title Complex Structure around a Circumstellar Disk Caused by Interchange Instability
topic Solar and Stellar Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2501.08701