Magnetic field evolution in solar-type stars
arXiv:2004.00439 · doi:10.1017/S1743921320001404
Abstract
We discuss selected aspects regarding the magnetic field evolution of solar-type stars. Most of the stars with activity cycles are in the range where the normalized chromospheric Calcium emission increases linearly with the inverse Rossby number. For Rossby numbers below about a quarter of the solar value, the activity saturates and no cycles have been found. For Rossby numbers above the solar value, again no activity cycles have been found, but now the activity goes up again for a major fraction of the stars. Rapidly rotating stars show nonaxisymmetric large-scale magnetic fields, but there is disagreement between models and observations regarding the actual value of the Rossby number where this happens. We also discuss the prospects of detecting the sign of magnetic helicity using various linear polarization techniques both at the stellar surface using the parity-odd contribution to linear polarization and above the surface using Faraday rotation.
13 pages, 3 figures, 3 tables, proceedings of IAU symposium 354, Solar and Stellar Magnetic Fields: Origins and Manifestations
References in corpus (9)
- Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
- Magnetic Cycles in a Convective Dynamo Simulation of a Young Solar-type Star
- Common dynamo scaling in slowly rotating young and evolved stars
- Magnetic twist: a source and property of space weather
- LBT/PEPSI Spectropolarimetry of a Magnetic Morphology Shift in Old Solar-type Stars
- Stellar Dynamos with Solar and Anti-solar Differential Rotations: Implications to Magnetic Cycles of Slowly Rotating Stars
- Far beyond the Sun: I. The beating magnetic heart in Horologium
- Global simulations of Tayler instability in stellar interiors: The stabilizing effect of gravity
- Helicity proxies from linear polarisation of solar active regions