Published online by Cambridge University Press: 12 April 2016
Data from the Einstein X-Ray satellite continue to provide useful information for studies of x-ray emitting objects. The Einstein Medium Sensitivity Survey (EMSS), a tabulation of serendipitously discovered point sources from the Einstein database, included a number of objects which were identified, on the basis of spot sampling of optical spectra, as likely binary star systems (Fleming 1988, Silva et al. 1987; Takalo & Nousek 1988). Because the sample is limited primarily by X-ray flux, the physical characteristics of these stars are of considerable interest for understanding the origins of stellar activity among cool stars.
Visiting Astronomer, Kitt Peak National Observatory, National Optical Astronomy Observatories, operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.
Some of the observations reported were obtained at the Multiple Mirror Telescope Observatory, a joint facility of the Smithsonian Institution and the University of Arisona.