Federico Spada (AIP)

Magnetic activity and fundamental parameters of solar-like stars
When Mar 22, 2013 from 10:30 AM to 12:00 PM
What
  • Colloquium
Where SH, Lecture hall
Add event to calendar vCal / iCal

I will present the construction of theoretical models of solar-like stars (i.e., 0.1 < M/Msun < 1.25) and their comparison with the best available observations.

As their name implies, solar-like stars share many properties with the Sun: they have outer convection zones, believed to be the seat of dynamo action, which in turn powers magnetic activity and, via the magnetic wind braking, drives a non-trivial rotational evolution. A long-standing issue in the theory of low-mass stars is the existence of a disagreement between models and observations: observed radii are ~ 10% larger and effective temperatures are ~ 5 % cooler than expected from theory. Interestingly, the R and Teff discrepancies compensate to give about the same luminosity, suggesting a surface origin of the
phenomenon.

Very precise measurements of stellar parameters, obtained from interferometry and double-lined eclipsing binaries, establish beyond doubt the reality of such a discrepancy; its correlation with magnetic activity and its possible resolution, based on stellar models including magnetic fields, will also be discussed.