In such a system, a black hole pulls gas from the surface of a companion star.

Finding new companion stars is not an especially rare event in astronomy.

Its companion star can be found with a small telescope.

The system is made up of a stellar mass black hole and a companion star.

The companion star also has an unusually large mass, 70 times that of the Sun.

If these two stars are close enough, material from one star can be pulled off the companion star's surface and onto the white dwarf.

This desert occurs because if a brown dwarf were to form, it would have to do so at the same time as its companion star.

A gas flow then develops from the companion star to the primary.

Our own sun appears to be unusual for not having a companion star.

The other possibility is mass transfer to a companion star.