A team of scientists, including nine from the U.K's Oxford University, has witnessed the last moments of a dying star as a ultraviolet flash betrayed signs of a shockwave just prior to the star's explosion seen as a supernova. Combining data from both ground-based telescopes monitoring visible light and space telescopes looking for ultraviolet light, the researchers followed light emanating from a dying star. A series of images captured by the team shows the moment a red supergiant star’s core collapsed in a galaxy a billion light years away from Earth. "Supernovae are huge stellar explosions that light up galaxies but often we have no idea which star has exploded." said Dr Kevin Schawinski of Oxford University’s Department of Physics in a university statement. "The nature of such an explosion is that we can’t look inside it and it destroys almost all evidence of the original star – scientists have been trying to catch such an event happening for decades."Scientists had previously been able to see stars nearly the end of their existence and the resulting supernova but not the happenings in between. The discovery gives scientists a better idea of the process the star goes through in its last hours of life.A burst of ultraviolet light given off by a red super-giant star in a galaxy around a billion light years away was detected by the team about two weeks before it was seen as a normal supernova. "We believe that this light, emanating from deep within the star, was generated after its core collapsed and compressed the gas surrounding it to around one million degrees Kelvin," said Dr Stephen Justham of Oxford University’s Department of Physics. According to the university statement, "Around four hours after this light was observed a shockwave from the collapsed core, travelling at 50 million kilometres an hour, would have hit the surface of the star and blown it apart. However, it was almost two weeks before the resulting fireball was spotted by supernova hunters using telescopes in Hawaii." "With this observation we have managed to peer inside one of the hundred billion stars in a galaxy and see what it is like at the very moment that it dies," said Dr Christian Wolf of Oxford University’s Department of Physics. "We’ve been extremely fortunate to capture this moment but this is just one event and, of course, we’d love to capture other similar events with different stars which could deliver many more surprises."The team's findings are published in this week's edition of Science.
Image: Supernova breakout. Courtesy Oxford University Press Office.
Interested in a more interactive TTH? Join our Facebook Group Want regular updates from The Tech Herald? Follow us on Twitter
Advertising
Comment on this Story