1. They’re vital for astrophysics
Observing binary star systems has enabled scientists to deduce the characteristics and make-up of various stars, as they are able to calculate the masses of stars and observe their spectroscopy as they influence one another.
2. Some orbit black holes
One famous binary system, located about 6,070 light years from Earth, consists of a blue supergiant star and a suspected black hole known as Cygnus X-1, the latter being 14.8 times the mass of the Sun.
3. Binary stars can be invisible
In some instances the second star of a binary system might be a dim brown dwarf or neutron star, only making itself apparent through its gravitational influence on its partner.
4. They cause supernovas
As two stars orbit one another they can transfer mass between them. This is the progenitor of a Type Ia supernova, when a star takes on so much mass it can no longer support itself and explodes.
5. 4 out of 5 stars are multiples
It is thought that as many as 80 per cent of all stars in the universe are part of multiple systems containing two or more stars; some theories even suggest our Sun is a binary star.