(Submitted October 02, 1996)
I'm wondering what information you have on the X-ray source Cygnus X-1
and on it's nearby star (a blue giant).
Cyg X-1 is believed to be a black hole binary, with a 20-35 solar mass
black hole and a O9.7Iab companion. The orbital period is 5.6 days. You
can learn more about black holes and X-ray binaries in Imagine the
Universe! in both the Basic Level and the Advanced Level. In particular,
the level 2
discusses the Cygnus X-1 binary starry system. It includes
some information on the blue giant companion to the unseen compact
object. The reading list at the end of the page also gives a number
of good books with a great deal of information about black holes:
since Cygnus X-1 is still considered to be one of the better black
hole candidates, all of these books discuss the binary system in some
We hope you'll take the time to browse through the sites and
"read more about it".