The emergence of the Md-Macc correlation in the MHD wind scenario

Fuente: arXiv
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Autores principales: Zallio, Luigi, Rosotti, Giovanni, Tabone, Benoît, Testi, Leonardo, Lodato, Giuseppe, Somigliana, Alice
Formato: Preprint
Publicado: 2024
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author Zallio, Luigi
Rosotti, Giovanni
Tabone, Benoît
Testi, Leonardo
Lodato, Giuseppe
Somigliana, Alice
author_facet Zallio, Luigi
Rosotti, Giovanni
Tabone, Benoît
Testi, Leonardo
Lodato, Giuseppe
Somigliana, Alice
contents There is still much uncertainty around the mechanism that rules the accretion of proto-planetary disks. In the last years, Magnetohydrondynamic (MHD) wind-driven accretion has been proposed as a valid alternative to the more conventional viscous accretion. In particular, winds have been shown to reproduce the observed correlation between the mass of the disk Md and the mass accretion rate onto the central star Macc, but this has been done only for specific conditions. It is not clear whether this implies fine tuning or if it is a general result. We investigate under which conditions the observed correlation between the mass of the disk Md and the mass accretion rate onto the central star Macc can be obtained. We find that, in the absence of a correlation between the initial mass M0 and the initial accretion timescale tacc,0, the slope of the Md-Macc correlation depends on the value of the spread of the initial conditions of masses and lifetimes of disks. Then, we clarify the conditions under which a disk population can be fitted with a single power-law. Moreover, we derive an analytical expression for the spread of log(Md/Macc) valid when the spread of tacc is taken to be constant. In the presence of a correlation between M0 and tacc,0, we derive an analytical expression for the slope of the Md-Macc correlation in the initial conditions of disks and at late times. We conclude that MHD winds can predict the observed values of the slope and the spread of the Md-Macc correlation under a broad range of initial conditions. This is a fundamental expansion of previous works on the MHD paradigm, exploring the establishment of this fundamental correlation beyond specific initial conditions.
format Preprint
id arxiv_https___arxiv_org_abs_2411_07227
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The emergence of the Md-Macc correlation in the MHD wind scenario
Zallio, Luigi
Rosotti, Giovanni
Tabone, Benoît
Testi, Leonardo
Lodato, Giuseppe
Somigliana, Alice
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
There is still much uncertainty around the mechanism that rules the accretion of proto-planetary disks. In the last years, Magnetohydrondynamic (MHD) wind-driven accretion has been proposed as a valid alternative to the more conventional viscous accretion. In particular, winds have been shown to reproduce the observed correlation between the mass of the disk Md and the mass accretion rate onto the central star Macc, but this has been done only for specific conditions. It is not clear whether this implies fine tuning or if it is a general result. We investigate under which conditions the observed correlation between the mass of the disk Md and the mass accretion rate onto the central star Macc can be obtained. We find that, in the absence of a correlation between the initial mass M0 and the initial accretion timescale tacc,0, the slope of the Md-Macc correlation depends on the value of the spread of the initial conditions of masses and lifetimes of disks. Then, we clarify the conditions under which a disk population can be fitted with a single power-law. Moreover, we derive an analytical expression for the spread of log(Md/Macc) valid when the spread of tacc is taken to be constant. In the presence of a correlation between M0 and tacc,0, we derive an analytical expression for the slope of the Md-Macc correlation in the initial conditions of disks and at late times. We conclude that MHD winds can predict the observed values of the slope and the spread of the Md-Macc correlation under a broad range of initial conditions. This is a fundamental expansion of previous works on the MHD paradigm, exploring the establishment of this fundamental correlation beyond specific initial conditions.
title The emergence of the Md-Macc correlation in the MHD wind scenario
topic Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2411.07227