Explanation:
Spectacular explosions keep occurring in the binary star system named
RS Ophiuchi.
Every 20 years or so, the
red giant star dumps enough
hydrogen
gas onto its companion white dwarf star to set off a brilliant
thermonuclear explosion on the
white dwarf's surface.
At about 2,000 light years distant, the resulting
nova explosions cause the
RS Oph system to brighten up by a huge factor and become visible to the unaided eye.
The red giant star is depicted on the right of the
above drawing,
while the white dwarf is at the center of the bright
accretion disk on the left.
As the stars orbit each other, a stream of
gas moves from the giant star to the white dwarf.
Astronomers speculate that at some time in the next 100,000 years, enough matter will have accumulated on the
white dwarf to push it over the
Chandrasekhar Limit,
causing a much more powerful and final explosion known as a
supernova.
