Astronomers have spotted what looks to be a bizarre triple star system not too far away, cosmically speaking, that’s engaged in a frantic and parasitic dance.
Researchers from MIT believe they’ve spotted a rare “black widow binary,” made up of a pulsar and a smaller companion star it’s slowly devouring as the two orbit each other, just as the female of the infamous spider species does to its mate.
This already unusual system is made more unique by what appears to be a third star circling the binary at a distance and taking 10,000 years to complete a single orbit.
The nature of the system still needs to be confirmed, so for now it’s being referred to as candidate ZTF J1406+1222. It’s about 3,000 light-years from Earth, which is pretty nearby for such an exotic object on the grand scale of the universe.
“This system has probably been floating around in the Milky Way for longer than the sun has been around,” said Kevin Burdge, from MIT’s department of physics, in a statement.
Burdge is lead author of a paper in this week’s issue of the journal Nature.
There’s a lot going on in this system. First you have a pulsar, which is the collapsed core of a massive star that rotates at a dizzying pace, completing a rotation every few milliseconds and sending out bursts of gamma and X-rays as it spins. The gravitational pull of this sadistic star is simultaneously sucking up gas and other material from its companion star. This acts as fuel to keep the pulsar going longer, essentially recycling its energy like something out of a magical fantasy story to give it the strength to keep cannibalizing its partner.
“These systems are called black widows because of how the pulsar sort of consumes the thing that recycled it, just as the spider eats its mate,” Burdge explains.
The system also has the shortest orbital period of any of the few dozen black widow binaries seen so far. The two stars take just 62 minutes to circle each other.
The researchers used a different technique to find this object than detecting gamma and X-rays, which is how most similar systems have been identified.
“This system is really unique as far as black widows go, because we found it with visible light, and because of its wide companion, and the fact it came from the galactic center,” Burdge says. “There’s still a lot we don’t understand about it. But we have a new way of looking for these systems in the sky.”
He adds that there’s one other odd thing about ZTF J1406+1222: The astronomers didn’t detect gamma or X-rays from the pulsar.
“Everything seems to point to it being a black widow binary. But there are a few weird things about it, so it’s possible it’s something entirely new.”