Spots and active regions on the emission-line star VY Ari

Quasi-simultaneous photoelectric and spectroscopic observations have been made of the active spotted star VY Ari, showing an increase in the equivalent width of pure emission in the Ha line with a decrease in the star's brightness. Such an increase indicates a relationship between active regions in the chromosphere and the cool photospheric spots. The photometric variability of VY Ari can be described entirely in terms of a zonal model. The spotted regions occupy up to 41% of the star's total surface, with the temperature difference between the quiet photosphere and a spot of 1300 K. The spots lie at middle and low latitudes. © 2001 Plenum Publishing Corporation.