Could This Star Have a Mysterious Invisible Partner?

Neutron stars are one of the few ways a star ends its life. They are formed from the remains of a massive star after it had already exploded into a supernova that condenses into an extremely dense core. They usually have masses 1.35 to about 2.1 times greater than that of our Sun, while being 30,000 to 70,000 times smaller than the Sun.

Observations of such a neutron star, called RCW103, seemed to contradict all astronomers knew about the evolution of these stars, because of contradicting data over unusually large variations in its X-ray emission over a period of years.

This star, located 10,000 light years away in the constellation Norma, is approximately 2000 years old and a powerful x-ray source of the supernova remnant it inhabits. It looks like a bright blue dot at the center of the remnant, which astronomers believe to have formed when the original star exploded.

New x-ray images of that region of space, taken by Chandra, seem to provide an intriguing possible explanation for the strange behavior of the tiny star, which is only 10 miles (16 km) wide but contains more mass than the entire Sun.

Astronomers are now inclined to believe that the reason why the neutron star near the center is rotating once every 6.7 hours, much slower than a neutron star of its age should be spinning, is a small and invisible companion in the gas cloud, that orbits the neutron star but is far too dim to be seen.

This star would have to have a low mass and could spew gas onto the neutron star, thus fueling its unusual x-ray emissions. Also, the interaction of the magnetic field of the two stars could have caused the neutron star to slow its rotation, thus explaining its second anomaly.

Further research is hoped to definitely prove this theory, but even now, it is the closest thing to a plausible explanation that astronomers have managed to come up with.