At this stage, the star becomes a large red giant. Because a red giant is so large ... greatly outshines its white dwarf companion, Sirius B. At 8.6 light-years away, Sirius B is the nearest ...

Scientists have detected emanating from the nucleus of a galaxy relatively close to our Milky Way flashes of X-rays gradually ...

Gravity then causes them to collapse and blow off their outer layers in a "red giant" stage ... to confirm that this is indeed a white dwarf using next-generation observatories such as Nasa's ...