As new stars are born in a binary system they grow to become red giant stars
, like the Sun, after the hydrogen needed for nuclear fusion runs out, notes the release.
suggests that the late-type giant star
is roche lobe filling, and that the outbursts are driven by an unsteady disc accretion, although this model has yet to reproduce the observed broad P Cygni profile.
Stars like our Sun expand and cool to become red giant stars
when the hydrogen that fuels the nuclear fusion in their cores starts to run out.
The researchers interpret this X-ray emission to be caused by the collision between supernova debris and disk-shaped material that the giant star
expelled before the explosion.
The remaining, gravitationally-crushed relic of that giant star
, most likely a black hole, feeds on gas from a very close, companion star.
If the companion were a star like ours, or even a giant star
, a sizeable portion of the debris blown away from the supernova would contain atoms of the element hydrogen.
Astronomers believe that this material was ejected by either a supernova or a giant star
in the region.
They believe that the heat created in six billion years' time, when our sun eventually swells into a giant star
, will warm the icy surface of one of Saturn's moons, Titan.
But does that white dwarf draw material from a Sun-like star, an evolved red giant star
, or from a second white dwarf, or is something more exotic going on.
For example, if the red giant star
that likely gave rise to the pulsar suddenly shed more than half its mass to form the new pulsar, the planet could not remain bound.
The new observations are sharp enough to show that the giant star
is smaller than previously thought, making it much more difficult to explain how the red giant lost matter to its companion.
Our Sun, for example, is expected to swell so that it nearly reaches or possibly engulfs Earth, as it becomes a red giant star