Astronomers discover a rare ’black widow’ binary star system

Astronomers know of about two dozen black widow binaries in the Milky Way. This newest candidate is 3,000 light-years from Earth.

 Artistic depiction of two neutron stars merging. (photo credit: Wikimedia Commons)
Artistic depiction of two neutron stars merging.
(photo credit: Wikimedia Commons)

Astronomers announced in a paper published Wednesday in Nature that they have discovered a rare type of binary star system.

The system, nicknamed a "black widow binary," consists of a rapidly spinning neutron star, or pulsar, that circles and slowly consumes a smaller companion star. The name is inspired by the black widow spider, which consumes its mate. 

The remarkable thing about this "black widow" in particular, is that, while the two main stars orbit each other every 62 minutes, there appears to be a distant third star that orbits the two inner stars every 10,000 years. 

The research team hypothesized that the triple system is likely derived from a once-dense constellation of old stars known as a globular cluster. This cluster may have drifted into the Milky Way's center, where the gravity of the central black hole pulled it apart but left the triplet intact. 

“Everything seems to point to it being a black widow binary,” according to co-author Kevin Burdge, a postdoctoral researcher at the Massachusetts Institute of Technology. “But there are a few weird things about it, so it’s possible it’s something entirely new.”

 View of the stars during a meteor shower in the skies above the Negev desert, near Ramon Lookout, in southern Israel, on August 13, 2018.  (credit: ROY ALIMA/ FLASH 90) View of the stars during a meteor shower in the skies above the Negev desert, near Ramon Lookout, in southern Israel, on August 13, 2018. (credit: ROY ALIMA/ FLASH 90)

The team will continue observing the triple black widow using a new optical technique that will hopefully make more stars visible and thus widen the context in which the system can be seen.