Spectroscopic evidence for nonuniform starspot properties on II Pegasi

摘要

We present spectroscopic evidence for multiple sport temperatures on the RS CVn star Pegasi(HD 224085). We model the strengths of the 7055 and 8860 A TiO absorption bands in the spectrum of II Peg using weighted Sums of inactive comparison spectra: a K star to represent the nonspotted photosphere and an M star to represent The spots. The best fit yields independent measurements of the starspot filling factor(f_s)and mean spot temperature ()averaged over the visible hemisphere of the star. During three-fourths of a rotation of II Peg in late 1996, we measure a constant f_s ≈55/100±5/100.