Radio & optical observation of UX Arietis

The light curves indicate that the maximum starspot visibility occurred very close to 0.0 phase, the same phase as the radio maxima. Closer comparison of our radio and optical light curves indicates that they are almost perfectly anticorrelated. A similar radio/optical correlation has been found by Lim et al. (1992ApJ...388L..27L) and Lim et al. (1994ApJ...430..332L) for the single K0 V star AB Dor.

We make the following conclusions from our observations. First, the episodes of long-term (~hours to days) radio flaring were modulated by stellar eclipses. Second, the flares were located close to the starspot groups.

Third, the sizes of the flares were comparable to sizes of the starspot groups, which is consistent with nonthermal emission of brightness temperature T_b~10^10-10^13K. Fourth, the radio emission arose only from the midlatitude starspot groups. Last, the radio flares emitted their radiation nearly normal to the stellar surface.