A very rare pair of stars is behaving very ‘weirdly’, scientists say
A newly discovered, very rare binary star system appears to be behaving very weirdly, according to the researchers who found it.
The system is so unusual that there are thought to be only be about 10 of them throughout our vast Milky Way galaxy.
It has all the conditions to go on and trigger a kilo nova, or the explosion that happens when neutron stars collide, triggering an ultra-powerful blast that can be detected across the universe.
The twin star system is bright in X-rays and high in mass, the astronomers who found it say. But it is particularly unusual because the two stars orbit around each other in what they say is a “weirdly circular” route.
It appears to have been formed when an exploding star or supernova fizzled out, rather than exploding with the usual dramatic bang.
Its weird orbit helped researchers find that one of the two stars is a “depleted” supernova. That meant that when the star consumed its fuel, and its core collapse, it had a relatively weak explosion.
Usually, that explosion kicks the stars into a long, elliptical orbit. But there wasn’t even enough energy left in the star to create such a blast, so the two stars instead stayed closely aligned in a round orbit.
The system is known as CPD-29 2176, and is situated about 11,400 light years from Earth. It was first spotted by Nasa’s Neil Gehrels Swift Observatory and it was later observations using the SMARTS 1.5-meter Telescope in Chile that confirmed its unusual nature.
The findings are described in a new paper, published in the journal Nature today, under the title ‘A high-mass X-ray binary descended from an ultra-stripped supernova’.
