Trends in torques acting on the star during a star-disk magnetospheric interaction
arXiv:2309.12383 · doi:10.1051/0004-6361/202243517
Abstract
We assess the modification of angular momentum transport in various configurations of star-disk accreting systems based on numerical simulations with different parameters. We quantify the torques exerted on a star by the various components of the flow in our simulations of a star-disk magnetospheric interaction. 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. We find that for all the stellar magnetic field strengths, B, 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, , 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 . The torque from a magnetospheric ejection is proportional to . 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.
arXiv comment15 pages, 57 figures, accepted in A&A
References in corpus (21)
- PLUTO: a Numerical Code for Computational Astrophysics
- Improved angular momentum evolution model for solar-like stars
- Accretion-powered Stellar Winds as a Solution to the Stellar Angular Momentum Problem
- Magnetic Braking Formulation for Sun-Like Stars: Dependence on Dipole Field Strength and Rotation Rate
- Launching of Conical Winds and Axial Jets from the Disk-Magnetosphere Boundary: Axisymmetric and 3D Simulations
- MHD simulations of accretion onto a dipolar magnetosphere. II. Magnetospheric ejections and stellar spin-down
- Improved angular momentum evolution model for solar-like stars II. Exploring the mass dependence
- Accretion funnels onto weakly magnetized young stars
- Magnetic propeller outflows
- Strongly magnetized accretion disks: structure and accretion from global magnetohydrodynamic simulations
- Warps, bending and density waves excited by rotating magnetized stars: results of global 3D MHD simulations
- Accretion discs around black holes: two dimensional, advection cooled flows
- Magnetic torques on T Tauri stars: accreting vs. non-accreting systems
- The Structure of Radiatively Inefficient Black Hole Accretion Flows
- Rotational evolution of solar-type protostars during the star-disk interaction phase
- From Stellar Coronæ to Gyrochronology: a theoretical and observational exploration
- Protostellar spin-down: a planetary lift?
- "Atlas" of numerical solutions for star-disk magnetospheric interaction
- Magnetic field structure and torque in accretion discs around millisecond pulsars
- Accretion disc backflow in resistive MHD simulations
- MHD simulations of resistive viscous accretion disk around millisecond pulsar