This proposal seeks to complete a program originally proposed by an HST staff member (Bond). I would like to insure that its contents remain confidential until after the review. Assigned ID: 15 ----- Attempting Submission 1 (Mon Feb 14 15:34:52 GMT 2011) ----- Classical novae (CN) result from a thermonuclear runaway on a white dwarf and produce the second most violent stellar eruptions in the Galaxy. While we have made considerable progress on understanding the outbursts of these systems, numerous issues remain. We now have a general idea of what drives the peak luminosity of the outburst and the speed at which the CN declines from maximum (white dwarf mass), but we have yet to properly calorimeter these outbursts due to the lack of precise distance information. More importantly, however, is understanding the mass lost during an eruption (could they be the progenitors of Type I supernovae?). To quantify this, we need to know the volume and filling factor of their ejected shells. This requires accurate distance information, as CN produce clumpy, prolate shells. Four CN have archival FGS data (from 40 orbits!) that have yet to be properly reduced and analyzed. We propose to extract these data from the archive, and produce high precision (+/-10%) parallaxes. As shown by our team's track record, we have the expertise to complete this project during Cycle 19.

HOT STARS 12 Medium false 0.0 0.0 false false false false SUPPORTED