Starspots are interesting to stellar astronomers because they are informed by the star’s rotation and circulation, details that are otherwise difficult to discern. Although starspots are too small to be imaged directly by current telescopes, they can be inferred from variations in a star’s light. CfA astronomer Raphaelle Haywood and two colleagues have analyzed archival data from the Kepler satellite to uncover some of the general properties of starspots. Kepler’s primary goal was the detection of exoplanets from periodic variations in starlight due to transits, but its steady monitoring of starlight revealed many other temporal phenomena, including starspots. From a set of over thirty-four thousand main-sequence stars, the astronomers selected 2244 with rotation periods between 9.5 and 20.5 days. They were able to group the observed starspot behavior into three categories based on their persistence, and reached three significant conclusions. One is that our Sun is not unusually quiet. The others are that bigger starspots live longer, and that the starspots on cooler stars decay more slowly. The conclusions are consistent with current models of starspots, but this work is the first large-scale survey of the phenomenon. Reference: “A Kepler Study of Starspot Lifetimes with Respect to Light-Curve Amplitude and Spectral Type” by Helen A. C. Giles, Andrew Collier Cameron and Raphaëlle D. Haywood, 2 August 2017, MNRAS.DOI: 10.1093/mnras/stx1931
