Some recent photometric and spectroscopic results for this "ultrashort" period system are summarized, and several straightforward consequences of these results for our understanding of the evolution...R. A. WadeUniversity of ArizonaSpringer NetherlandsInternational Astronomical Union Colloquium...
The secondary star does not lie on the computed evolutionary tracks in the period-mass diagram of Paczynski and Sienkiewicz.doi:10.1007/BF00668135R.A.WadeKluwer Academic PublishersAstrophysics&Space Science