Starspots: Observation of photosphere, chromosphere, vs. corona

From top to bottom the X-ray, UV, and optical folded light curves are shown. Each folded light curve is binned at bin-size 0.1. The figure shows the rotationally modulated X-ray, UV (uvm2 filter), and optical (V band) light curves. Observations of the year 2008 were used for rotational modulation, where we have removed the flaring feature from X-ray light curve. Optical and X-ray observations are ∼100 d apart. It appears that both X-ray and UV light curves were rotationally modulated. X-ray and UV light curves appear to be anti-correlated with V-band light curve. The Pearson correlation coefficients between X-ray and V band, and UV and V-band light curve were found to be −0.22 and −0.57, respectively.

[Image Credit: Karmakar et al. (2016)]