| Astronomers have had their first ever grandstand view of a dramatic collision between two stars. The ‘cosmic car crash’ created a new type of explosion that had not previously been recognised in the universe.
Californian astronomers detected the blast while using a telescope at Lick Observatory to search for suicide stars blowing themselves to pieces as supernovae. When they turned their telescope on a galaxy called Messier 85, in the constellation of Coma Berenices, they recorded an explosion that was not powerful enough for a supernova. However, it was also too bright to be an ordinary nova – a star that occasionally throws of a shell of hot gas in a thermo-nuclear eruption. It beame clear that the blast was probably caused by two ordinary stars smashing into each other. The event has been labelled M85OT2006-1. Team leader Professor Shrinivas Kulkarni, of the California Institute of Technology, had been speculating on possible new classes of cosmic explosion other than novae, supernovae and gamma-ray blasts. Astronomers mounted a major follow-up program of observations with giant telescopes in California, Hawaii and Chile. Colleague Dr Arne Rau said: “I was simply floored. In a short time we went from speculation to a real discovery. It was an exciting moment for me.” The galaxy Messier 85 is mainly made up of old stars and the astronomers believe that the stellar victims were probably of similar mass to the sun. They also believe that a similar event was detected in the nearby Andromeda galaxy, Messier 31, more than a decade ago, but was poorly studied. Last year, we reported how astronomers had witnessed the start of a supernova explosion for the first time. Photo: This image of Messier 85 was taken by the 0.9-meter telescope at Kitt Peak. Credit: National Optical Astronomy Observatory/Association of Universities for Research in Astronomy/National Science Foundation. |
