Tracing Detailed Starspot Evolution with Kepler
Abstract
Modeling sinusoidal flux variations in high precision photometry due to starspots, and their evolution over time, reveals critical information about the strength and nature of stellar magnetic fields. Photometry from the Kepler mission has discovered the presence of cool starspots on the surfaces of thousands of main sequence stars. Here we show preliminary results from our campaign to model the detailed time evolution of starspots on four stars. The rapidly rotating M4 star, GJ 1243, exhibits a remarkably stable polar starspot spanning three years of observation. A secondary polar spot is also seen, with an evolution timescale of hundreds of days. Three G/K stars with a wide range of rotation periods have also been studied, KOI-63, Kepler 17, and HAT-P-11. These systems all have planetary transits in their light curves, which we exploit to break degeneracies between spot surface coverage area and spot latitude. These transits can also probe smaller-scale starspot features on the stellar surface along a fixed latitude. By modeling the in- and out-of-eclipse light curves (see corresponding poster by L. Hebb) we are able to trace the detailed starspot evolution for several years in each system. This will help to constrain key physical parameters, such as mean rotation period, differential rotation, and diffusion timescales.
- Publication:
-
American Astronomical Society Meeting Abstracts #223
- Pub Date:
- January 2014
- Bibcode:
- 2014AAS...22331503D