Hubble sees gas shell around Nova Cygni 1992

A NASA/ESA Hubble Space Telescope (HS1) image of a tepidly ballooning bubble of gas blasted off a star. The shell surrounds Nova Cygni 1992 which erupted on February 19, 1992. The shell is so young it still contains a record of the initial conditions of the explosion.

The HST image was taken in ultraviolet light with the European Space Agency's Faint Object Camera (FOC) on May 31, 1993, 467 days after the explosion. The FOC reveals a remarkably circular yet slightly lumpy ring-like structure. The ring is the edge of the bubble's shell of hot gas. The shell is only 37 billion miles (about 60 billion kilometres) across, or 400 times the diameter of the solar system. A beam of light could cross the shell in less than 2-1/2 days.