Core-envelope decoupling drives radial shear dynamos in cool stars
Abstract
Differential rotation is thought to be responsible for the dynamo process in stars like our Sun, driving magnetic activity and star spots. We report that star spot measurements in the Praesepe open cluster are strongly enhanced only for stars which depart from standard models of rotational evolution. A decoupling of the spin down history between the core and envelope explains both the activity and rotation anomalies: surface rotational evolution is stalled by interior angular momentum redistribution, and the resultant radial shears enhance star spot activity. These anomalies provide evidence for an evolving front of shear-enhanced activity affecting the magnetic and rotational evolution of cool stars and the high-energy environments of their planetary companions for hundreds of millions to billions of years on the main sequence.
Keywords
Cite
@article{arxiv.2301.07716,
title = {Core-envelope decoupling drives radial shear dynamos in cool stars},
author = {Lyra Cao and Marc H. Pinsonneault and Jennifer L. van Saders},
journal= {arXiv preprint arXiv:2301.07716},
year = {2023}
}
Comments
13 pages, 8 figures. Accepted for publication in ApJ Letters