Saturday, May 2, 2015
Does a Real-Life Death Star Exist?
No, I’m not talking about something from the movies. That star would need to get close to a planet to destroy it. WR104, however, has the potential to burn worlds from thousands of light years away. This is Wolf-Rayet 104 located in the constellation of Sagittarius about 2,222 parsecs away. Okay, that’s about 8,000 light-years from us which may seem like a safe distance, but consider that WR104 is 25 times the size of our sun, very dense, and much, much hotter. Add to that mix the fact that this star is rotating rapidly and expelling its gases creating a spiral around it; it is dying.
At this level of brightness the radiation field around the star takes on a life of its own and plays a most unusual role; it sheds off the outer atmosphere of the star by photon pressure. Therefore, Wolf-Rayet stars are so luminous that they are literally flying apart! This creates a high-velocity stellar wind surrounding the star which first grabbed the attention of astronomers. Wolf-Rayet stars are very rare, only 230 have been discovered, so far, in our Milky Way Galaxy. Of these stars, half of them have a binary companion star which burns just as hot as the main star.
First discovered in 1998 by the Keck 1 Telescope, this star was photographed, studied, measured, and cataloged. Scientists were first taken by the size and beauty of this spiral image. They determined the diameter to be 160AU (Astronomical Units), which is 160 times the distance from Earth to the sun. Peter Tuthill, at the University of Sydney in Australia, has been studying WR104 for years. He realized it rotated in a circle every eight months and found one devastating fact: Earth looks down the axis of the system. We are not looking at it from an angle, but dead-on, like looking down the barrel of a rifle.
Another fact which concerns astronomers is that WR104 is not a single star system, rather a binary system. It has another Class OB star locked in orbit with it. As they circle one another, plumes of streaming gas are driven from their surfaces creating a fiery, colorful pinwheel in space. Astronomers fear the fuse for this star is very short; it may explode within the next few hundred thousand years. When it does it may emit an intense beam or ‘gamma ray burst.’ It is impossible to predict whether or not it will actually create the dreaded gamma ray beam directed at Earth; the exact outcome is still unknown. Some reports say, “Not to worry,” others say, “Earth is in line with a death-star.” I say, it’s a long time away; we have more important things to worry about until then.
For an image of WR104 visit: http://www.space.com/5081-real-death-star-strike-earth.html
My Sources: Astro Dept. at University of Michigan, nature.com/news, dailygalaxy.com, popsci.com, science.time.com, universetoday.com, space.com, and en.wikipedia.org