Editor's Announcement

Two new magnetic white dwarf accretion binaries with extremely lowmass-transfer rates have been discovered in the course of the Sloan Digital SkySurvey. Measured magnetic fields are 42 MG and 57 MG, and one system orbitswith a period of just 82 min. The new systems therefore significantly expandthe range in properties exhibited by the small class. The measured accretionrates are very low, 0.6-5x10^{-13} Msun/yr, and multiple visits spanning morethan a year confirm that this is not a short-lived characteristic. It isbecoming increasingly clear that the low-mdot magnetic white dwarf binariesaccrete by nearly complete magnetic capture of the stellar wind from thesecondary star rather than by Roche lobe overflow. The accretion ratestherefore provide some of the first realistic estimates of the total wind lossrates from M dwarfs. Although one or more of the eight systems known to datemay be interrupted or possibly even extinct Polars, several lines of evidencesuggest that most are pre-Polars whose evolution has not yet brought thesecondaries into contact with their Roche surfaces. Considering thedifficulties of identifying binaries over a wide range in field strength andaccretion rate, it is quite possible that the space density of wind-accretingmagnetic binaries exceeds that of the classical X-ray emitting, Roche-lobeoverflow Polars.Comment: 6 pages, 5 figure