In all likelihood this is a binary star system containing a low-mass normal star and a nonluminous companion.
In 2005 astronomers found that Eta Carinae is, in fact, a binary star system with an orbital period of 5.52 years.
If the images of the two components of a binary star system can be separated by telescope, it is called a visual binary.
Eta Carinae, also called Homunculus Nebula, peculiar red star and nebula about 7,500 light-years from Earth in the southern constellation Carina and now known to be a binary star system.
The planet Kepler-16b is part of an eclipsing binary star system where the stars and planet pass in front of one another periodically blocking some of the light from the telescope on board Kepler.
Although no light can be detected coming from within a black hole, the presence of a black hole may be manifested through the effects of its gravitational field, as, for example, in a binary star system.
In 2005 astronomers studying far-ultraviolet spectral observations of Eta Carinae made by spacecraft found that it is a binary star system with an orbital period of 5.54 years.
In an eclipsing variable, one member of a double, or binary, star system partially blocks the light of its companion as it passes in front of the latter, as observed from Earth.
For example, if a black hole is a member of a binary star system, matter flowing into it from its companion becomes intensely heated and then radiates X-rays copiously before entering the event horizon of the black hole and disappearing forever.
Now two astronomers have found a second dusty ring, this one around a binary star system.
The radial velocity measurements confirmed that the binary star system was actually speeding away from us.
