The object, first spotted in 1992, was confirmed to be a neutron star in 1996. But only now has its distance from Earth been determined, using data provided by the Hubble Space Telescope . The object, also described as the corpse of a star, currently is about 200 light-years away. It is due to pass by Earth in about 300,000 years, but will safely miss by about 170 light-years. Because the neutron star, called RX J185635-3754, is relatively nearby and all by itself, astronomers will be able to glean valuable information about star formation by studying it.
Most neutron stars are hard to study as they are a billion or more light-years away.
Researchers say that RX J185635-3754 was probably shot like a cannonball when its larger companion star exploded as a supernova a million years ago. The other star, now a hot blue star, has been seen racing in another direction. Calculations show that the two were likely orbiting each other before the explosion in a configuration known as a binary star system. The explosion would have been visible to our earthly ancestors in about 1 million B.C., scientists say. Supernova explosions are very complex and not well understood.