Magnetically threaded accretion disks in resistive magnetohydrodynamic simulations and asymptotic expansion

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F47813059%3A19630%2F23%3AA0000263" target="_blank" >RIV/47813059:19630/23:A0000263 - isvavai.cz</a>

Result on the web

<a href="https://www.aanda.org/articles/aa/full_html/2023/10/aa40637-21/aa40637-21.html" target="_blank" >https://www.aanda.org/articles/aa/full_html/2023/10/aa40637-21/aa40637-21.html</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202140637" target="_blank" >10.1051/0004-6361/202140637</a>

Result language

angličtina

Original language name

Magnetically threaded accretion disks in resistive magnetohydrodynamic simulations and asymptotic expansion

Original language description

Aims. A realistic model of magnetic linkage between a central object and its accretion disk is a prerequisite for understanding the spin history of stars and stellar remnants. To this end, we aim to provide an analytic model in agreement with magnetohydrodynamic (MHD) simulations.Methods. For the first time, we wrote a full set of stationary asymptotic expansion equations of a thin magnetic accretion disk, including the induction and energy equations. We also performed a resistive MHD simulation of an accretion disk around a star endowed with a magnetic dipole, using the publicly available code PLUTO. We compared the analytical results with the numerical solutions, and discussed the results in the context of previous solutions of the induction equation describing the star-disk magnetospheric interaction.Results. We found that the magnetic field threading the disk is suppressed by orders of magnitude inside thin disks, so the presence of the stellar magnetic field does not strongly affect the velocity field, nor the density profile inside the disk. Density and velocity fields found in the MHD simulations match the radial and vertical profiles of the analytic solution. Qualitatively, the MHD simulations result in an internal magnetic field similar to the solutions previously obtained by solving the induction equation in the disk alone. However, the magnetic field configuration is quantitatively affected by magnetic field inflation outside the disk; this is reflected in the net torque. The torque on the star is an order of magnitude larger in the magnetic than in the non-magnetic case. Spin-up of the star occurs on a timescale comparable to the accretion timescale in the MHD case, and is an order of magnitude slower in the absence of a stellar magnetic field.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

<a href="/en/project/GX21-06825X" target="_blank" >GX21-06825X: Accreting Black Holes in the new era of X-ray polarimetry missions</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2023

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

ASTRONOMY &amp; ASTROPHYSICS

ISSN

0004-6361

e-ISSN

—

Volume of the periodical

678

Issue of the periodical within the volume

Oct 2023

Country of publishing house

FR - FRANCE

Number of pages

16

Pages from-to

„A57-1“-„A57-16“

UT code for WoS article

001142864300001

EID of the result in the Scopus database

2-s2.0-85174198493