Saturday, January 25, 2014
A Star Explodes in a Nearby Galaxy
The big news from the world of astronomy is that a star has blown itself to pieces in a galaxy not so far, far away. The galaxy has the catalog number M82, and is only between 11 and 12 million light years away. (The nearest independent galaxy is a bit more than 2 million light years away, so, as galaxies go, M82 is one of our neighbors.)
M82 is located in the constellation of Ursa Major (the Big Bear), the same constellation that contains the well-known star pattern called the "Big Dipper." That means it is an easy target for telescopes in the Northern Hemisphere of our planet right now. Both amateur and professional astronomers are glued to their instruments, viewing and analyzing this doomed star.
Our color image, which shows the explosion -- called a supernova -- with an arrow, is from the Katzman Automatic Imagining Telescope at the Lick Observatory near San Jose (It was sent to me by Berkeley astronomer Alex Filippenko, who leads the project to discover exploding stars with this telescope.)
Astronomers are looking at the spectrum (the many different colors of light) from the exploding star. They have already discovered that this is that special kind of supernova which helped astronomers discover that the expansion of the entire universe is speeding up -- and earned them the 2011 Nobel Prize in physics.
Called a Type Ia supernova, this kind of explosion comes when a star corpse called a white dwarf is briefly re-ignited by sucking material from a close neighbor star (don't make any zombie jokes, please.) The energies involved when the white dwarf is overloaded with hot new material and blows up are so great that there is no earthly counterpart to compare them to. We are already seeing material blasting away from the explosion at speeds of 45 million miles per hour!!!
Since these supernovae are so important for understanding the universe (not just its expansion, but also its extent and how the death of old stars leads to the birth of the next generation), we are always grateful to have a nearby example to study.
If you have a telescope and want more information on how to find the galaxy and what equipment you will need to observe the supernova, see the Supernova 2014J pages at the website of Sky & Telescope magazine:http://www.skyandtelescope.com/observing/highlights/Bright-Supernova-in-M82-241477661.html