Trends in torques acting on the star during a star-disk magnetospheric interaction

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F47813059%3A19630%2F23%3AA0000264" target="_blank" >RIV/47813059:19630/23:A0000264 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.aanda.org/articles/aa/full_html/2023/11/aa43517-22/aa43517-22.html" target="_blank" >https://www.aanda.org/articles/aa/full_html/2023/11/aa43517-22/aa43517-22.html</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202243517" target="_blank" >10.1051/0004-6361/202243517</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Trends in torques acting on the star during a star-disk magnetospheric interaction

Popis výsledku v původním jazyce

Aims. We assess the modification of angular momentum transport in various configurations of star-disk accreting systems based on numerical simulations with different parameters. In particular, we quantify the torques exerted on a star by the various components of the flow and field in our simulations of a star-disk magnetospheric interaction. Methods. In a suite of resistive and viscous numerical simulations, we obtained results using different stellar rotation rates, dipole magnetic field strengths, and resistivities. We probed a part of the parameter space with slowly rotating central objects, up to 20% of the Keplerian rotation rate at the equator. Different components of the flow in star-disk magnetospheric interaction were considered in the study: a magnetospheric wind (i.e., the "stellar wind") ejected outwards from the stellar vicinity, matter infalling onto the star through the accretion column, and a magnetospheric ejection launched from the magnetosphere. We also took account of trends in the total torque in the system and in each component individually. Results. We find that for all the stellar magnetic field strengths, B-star, the anchoring radius of the stellar magnetic field in the disk is extended with increasing disk resistivity. The torque exerted on the star is independent of the stellar rotation rate, Omega(star), in all the cases without magnetospheric ejections. In cases where such ejections are present, there is a weak dependence of the anchoring radius on the stellar rotation rate, with both the total torque in the system and torque on the star from the ejection and infall from the disk onto the star proportional to Omega B-star(3). The torque from a magnetospheric ejection is proportional to Omega(4)(star). Without the magnetospheric ejection, the spin-up of the star switches to spin-down in cases involving a larger stellar field and faster stellar rotation. The critical value for this switch is about 10% of the Keplerian rotation rate.

Název v anglickém jazyce

Trends in torques acting on the star during a star-disk magnetospheric interaction

Popis výsledku anglicky

Aims. We assess the modification of angular momentum transport in various configurations of star-disk accreting systems based on numerical simulations with different parameters. In particular, we quantify the torques exerted on a star by the various components of the flow and field in our simulations of a star-disk magnetospheric interaction. Methods. In a suite of resistive and viscous numerical simulations, we obtained results using different stellar rotation rates, dipole magnetic field strengths, and resistivities. We probed a part of the parameter space with slowly rotating central objects, up to 20% of the Keplerian rotation rate at the equator. Different components of the flow in star-disk magnetospheric interaction were considered in the study: a magnetospheric wind (i.e., the "stellar wind") ejected outwards from the stellar vicinity, matter infalling onto the star through the accretion column, and a magnetospheric ejection launched from the magnetosphere. We also took account of trends in the total torque in the system and in each component individually. Results. We find that for all the stellar magnetic field strengths, B-star, the anchoring radius of the stellar magnetic field in the disk is extended with increasing disk resistivity. The torque exerted on the star is independent of the stellar rotation rate, Omega(star), in all the cases without magnetospheric ejections. In cases where such ejections are present, there is a weak dependence of the anchoring radius on the stellar rotation rate, with both the total torque in the system and torque on the star from the ejection and infall from the disk onto the star proportional to Omega B-star(3). The torque from a magnetospheric ejection is proportional to Omega(4)(star). Without the magnetospheric ejection, the spin-up of the star switches to spin-down in cases involving a larger stellar field and faster stellar rotation. The critical value for this switch is about 10% of the Keplerian rotation rate.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

<a href="/cs/project/GX21-06825X" target="_blank" >GX21-06825X: Akreující černé díry v nové éře polarizačních rentgenových misí</a><br>

Návaznosti

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

Rok uplatnění

2023

Kód důvěrnosti údajů

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

Název periodika

ASTRONOMY &amp; ASTROPHYSICS

ISSN

0004-6361

e-ISSN

—

Svazek periodika

679

Číslo periodika v rámci svazku

Nov 2023

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

14

Strana od-do

„A16-1“-„A16-14“

Kód UT WoS článku

001096229100009

EID výsledku v databázi Scopus

2-s2.0-85176357192