In 2010 the Fermi-LAT reported a surprising discovery: detection of a gamma ray transient that appeared to come from a nova, V407 Cyg. Since V407 Cyg is a special type of nova, however, it was considered a one-off event. Now two other classical novae have also been found in gamma rays.
Novae are thermonuclear explosions that occur on the surface of a white dwarf following the accretion of matter from a nearby companion star. The authors seek to understand the geometry and velocity of the ejected material.
Scientists propose way in which we could observe the envelope being ejected from binaries going through a common envelope phase. And their predictions match a class of objects which have already been observed.