Stellar Midlife Crises: Challenges and Advances in Simulating Convection and Differential Rotation in Sun-like Stars

摘要

Low mass, main sequence stars like our Sun exhibit a wide variety of rotational and magnetic states. Observational and theoretical advances have led to a renewed emphasis on understanding the rotational and magnetic evolution of sun-like stars has become a pressing problem in stellar physics. We use global 3D convection and convective dynamo simulations in rotating spherical shells and with realistic stellar stratification to explore the behavior of "middle-aged" stars. We show that for stars with slightly less rotational influence than our Sun a transition occurs from solar-like (fast equator, slow poles) to anti-solar (slow equator, fast poles) differential rotation. We investigate this transition using two different treatments for the upper boundary of our simulations and we hypothesize that this transition from solar-like to anti-solar differential rotation may be responsible for observations of anomalously rapid rotation for stars older than our Sun.