The Hubble Space Telescope Observations of X-Ray Nova MUSCAE 1991 and Its Spectral Evolution
Panagia, N.; Horne, Keith; Shrader, C. R.; Paresce, F.; Lund, N.; Cheng, F. H.; Gilmozzi, R.
United States, China, Denmark
Abstract
Hubble Space Telescope Faint Object Spectrograph (FOS) Faint Object Camera (FOC) and observations of Nova Muscae 1991 obtained on May 14-15, 1991 are presented and discussed. A nearly featureless continuum with broad 2200 A absorption feature and no Balmer jump is found. The FOS spectrum is modeled, including previous multiepoch IUE, optical, and X-ray data using a simple blackbody accretion disk model. It is found that the mass transfer rate decays exponentially with a characteristic time of about 43 days. The cooling front predicted by the disk instability model should have been observable, but was not seen.