Imaging the shell of nova Cygni 1992 with HST.

Abstract

The Faint Object Camera (FOC) on the Hubble Space Telescope (HST) observed Nova Cyg 1992 on May 31, 1993 in the UV. The images reveal a bright, well defined, circular, inhomogeneous ring of emission of 0.13 sec radius centered on the star. The data indicate that the ring is most likely due to a thin, limb-brightened shell of emitting material of radius 400 AU and thickness approximately equals 4 AU located at a distance of 3200 parsecs from the Sun. This represents the earliest detection of a resolved nova shell yet achieved providing a unique opportunity to better understand the nova mechanism.