How Does a Protostar Form by Magnetized Gravitational Collapse?

Fuente: arXiv
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Main Authors: Das, Indrani, Shang, Hsien, Krasnopolsky, Ruben
Format: Preprint
Published: 2025
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author Das, Indrani
Shang, Hsien
Krasnopolsky, Ruben
author_facet Das, Indrani
Shang, Hsien
Krasnopolsky, Ruben
contents Star formation through the dynamical magnetized collapse remains an active area of astrophysical research. We carry out a comprehensive exploration on the magnetized gravitational collapse of a non-rotating self-gravitating initially spherically symmetric prestellar cloud core using two-dimensional nonideal magnetohydrodynamic simulations incorporating ambipolar diffusion and Ohmic dissipation. Our study encompasses a broader range of equations of state (EOSs) in the form of $P(ρ) \propto ρ^Γ$, with the aim of constraining the choice of EOSs for allowing star formation. Our results reveal that the collapse with a $Γ$ no stiffer than $4/3$, complemented by magnetized virial theorem, allows the dynamical contraction of the prestellar core to happen continuously where a central point mass forms and steadily builds up its mass from the infalling envelope, with a mass accretion rate of a scale of the order of $c_{\rm s}^3/G$. The choice of an isothermal EOS most naturally facilitates the collapse as a magnetic analog of the inside-out collapse. In addition to that, our study exhibits that the nonisothermal magnetized collapse models with a $Γ$ no stiffer than 4/3 qualitatively demonstrate similar infall features to those of an isothermal EOS. Furthermore, the collapse models with a $Γ$ stiffer than $4/3$ fail to ensure the sufficient cooling to allow the direct mass growth of the central point mass, thus delaying the infall. Our work can offer deeper insights in understanding the significance of EOSs on the magnetized gravitational collapse, enabling star formation.
format Preprint
id arxiv_https___arxiv_org_abs_2502_17530
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle How Does a Protostar Form by Magnetized Gravitational Collapse?
Das, Indrani
Shang, Hsien
Krasnopolsky, Ruben
Astrophysics of Galaxies
High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
Star formation through the dynamical magnetized collapse remains an active area of astrophysical research. We carry out a comprehensive exploration on the magnetized gravitational collapse of a non-rotating self-gravitating initially spherically symmetric prestellar cloud core using two-dimensional nonideal magnetohydrodynamic simulations incorporating ambipolar diffusion and Ohmic dissipation. Our study encompasses a broader range of equations of state (EOSs) in the form of $P(ρ) \propto ρ^Γ$, with the aim of constraining the choice of EOSs for allowing star formation. Our results reveal that the collapse with a $Γ$ no stiffer than $4/3$, complemented by magnetized virial theorem, allows the dynamical contraction of the prestellar core to happen continuously where a central point mass forms and steadily builds up its mass from the infalling envelope, with a mass accretion rate of a scale of the order of $c_{\rm s}^3/G$. The choice of an isothermal EOS most naturally facilitates the collapse as a magnetic analog of the inside-out collapse. In addition to that, our study exhibits that the nonisothermal magnetized collapse models with a $Γ$ no stiffer than 4/3 qualitatively demonstrate similar infall features to those of an isothermal EOS. Furthermore, the collapse models with a $Γ$ stiffer than $4/3$ fail to ensure the sufficient cooling to allow the direct mass growth of the central point mass, thus delaying the infall. Our work can offer deeper insights in understanding the significance of EOSs on the magnetized gravitational collapse, enabling star formation.
title How Does a Protostar Form by Magnetized Gravitational Collapse?
topic Astrophysics of Galaxies
High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2502.17530