Pairs of stars might drive parcels of gas together and produce gamma rays
S. Wiessinger/NASA Goddard Space Flight Center
New observations might explain why explosions on three nearby white dwarfs, the cores of dead stars, recently belched out gamma rays (SN: 9/20/14, p. 15). The discovery stumped researchers because no one expected this type of eruption, called a nova, to produce such high-energy light.
Novas are thermonuclear blasts on the surfaces of white dwarfs that have gorged themselves on gas from a companion star. To spit out gamma rays, the blast needs to run into more gas, which is absent around typical novas.