Summary: Radio Characteristics of Cool Stars and the HRD
Manuel G¨udel and Marc Audard
Paul Scherrer Institut, W¨urenlingen & Villigen, CH5232 Villigen PSI,
Abstract. We discuss statistical properties of nonflaring radio emis
sion of a large sample of active stars and binaries. Various radio Hertz
sprungRussell Diagrams are presented.
Radio emission is routinely observed from a number of stellar classes, yet its
value as a diagnostic means has often been neglected if not dismissed. Every
so often radio observations have been added to large campaigns as corollary
information on variability, or as complementary illustrations that highenergy
processes occur in stellar atmospheres.
But can radio emission be used as a window to access stellar activity in its
own right, in a systematic and comprehensive way? Does radio emission reflect
fundamental properties of stellar atmospheres much like Xray radiation is a
tracer of the coronal thermal energy?
Radio emission from stars is comparatively difficult to detect. Measuring
the Sun's nonflaring radio emission at the distance of the nearest star (1.3 pc)
would be a challenge for the VLA, with integration times of 10 hours at the