The Sun Among the Stars: How Reliable is our Picture?

Richard R. Radick

Air Force Research Laboratory, Sunspot, NM, 88349

It is widely believed that the observed 0.1% cyclic variation of the Sun's total irradiance arises from the presence of dark sunspots and bright magnetic faculae on the solar surface. While it has been known for decades that other lower main-sequence stars display behavior interpretable as magnetic activity, exploration of the technically challenging regime of stellar photometric variability at amplitudes approaching 0.1% has been slow and painstaking. Nevertheless, measurements now exist that permit a preliminary comparison of solar variability with its stellar analogs, a comparison that suggests the Sun's variability is fairly typical for a star of its age and mass. Among the numerous vexations encountered in reconciling the solar and stellar measurements, problems arising from comparison of star variability and inclination effects seem to be among the more important.

The text of this talk has been submitted to The Astrophysical Journal, and is available as a preprint from the author upon request.