Starspot activity in late stars: Methods and results

Abstract

Three types of methods for studying the surface inhomogeneities of cool stars and the results of their use on type BY Dra, RS CVn, FK Com, and T Tau variables are discussed. The current relevance of traditional photometric methods and the advantages of the zonal spottedness model are pointed out. Dependences of the maximum total areas, average latitudes, and temperatures of spots on the global parameters of the stars are given. Analogs of the solar cycle in the variations of the areas and latitudes of starspots are examined, as well as the effects of differential rotation and active longitudes.

The Transit Light Curve Project. III. Tres Transits of TrES‐1

“…Thus we can set an approximate 2σ upper limit of f < 4 × 10 −4 on the product of the areal ratio and intensity contrast of small, circular star spots. This upper bound is too weak to rule out Sun-like starspots (f < ∼ 7 × 10 −6 ), 6 although the spots on later-type stars like TrES-1 are expected to be more prominent than sunspots (see, e.g., Alekseev 2006). We can rule out flux anomalies as large as the one seen by Brown et al, but there is no real contradiction because the observations were taken over a year apart.…”