Star sent hurtling across space at record speed following supernova explosion

Zipping at 1,200kps, a lonely star in our galaxy has broken the records for galactic speed, say astronomers at Queen's University Belfast.

The star will probably exit the Milky Way eventually. The unbound star, named US708, is moving at the fastest speed ever recorded for such an object in our galaxy.

The star is a rapidly rotating, compact helium star. It is believed to have once been part of a double-star solar system including a massive white dwarf star, transferring helium to the dwarf star and causing a thermonuclear explosion.

It is the exploding white dwarf that is believed to have turned into a 'thermonuclear supernovae' and sent US708 hurtling into space.

European Southern Observatory fellow, Stephan Geier, who led the study, said: "Several types of stars have been suspected of causing the explosion of a white dwarf as supernova of type Ia. Until now, none of them could be confirmed. Now we have found a delinquent on the run bearing traces from the crime scene."

Thermonuclear, or 'type Ia', supernovae have long been used to calculate the distances to faraway galaxies and determine how the universe is changing and expanding.

Dr Rubina Kotak and Ken Smith, from the Astrophysics Centre at Queen's University, were part of the team who detected the hurtling star using data gathered by the Pan-STARRS1 telescope on Mount Haleakala on the Hawaiian island of Maui.

Using data from the last 59 years the team was able to determine the full 3-D motion of the star and measure how quickly it is moving across the plane of the sky.

Dr Rubina Kotak said: "It is very exciting to have contributed to this important discovery which is a great example of Queen's commitment to achieving excellence and advancing knowledge for the benefit of society. It brings us a step closer to solving the type Ia puzzle."

An object far beyond the Local Group (collection of around 75 galaxies including Milky Way) was seen exiting at 1,026kps a few years ago, beating the earlier record of 780kps set by a star in the Andromeda Galaxy.

Greater velocities have been recorded when jets or explosions shoot debris.

Jupiter-sized blobs of hot gas in streams of material ejected from hyperactive galaxies known as blazars are known to move at near light speed of 299,800kps.

The ultra high-energy cosmic rays that slam into Earth's atmosphere are travelling at around 99.9% of the speed of light.

Most stars orbit the galactic centre at speeds of approximately 220kps. Our Sun moves at an estimated speed of 225kps, taking 225 million years for one revolution.

However, the present discovery is significant as it deals with a stellar object travelling at enormous speed.

Read the full research article at: http://www.sciencemag.org