Super Stars

                          


                    

Scientists in California have discovered a new way that stars explode. The discovery hinges on an unusual explosion in the galaxy NGC 1821, roughly 160 million light years away, according to astronomer Dovi Poznanski of the Lawrence Berkeley National Laboratory. Light from the exploding star reached Earth in 2002 and was recorded by a robotic telescope at Lick Observatory, near San Jose, Calif.  Credit: Tony Piro (2005)

Caroline Moore, a 14-year-old from Warwick, N.Y., has made a mark on astronomy with the discovery of Supernova 2008ha. Not only is she the youngest person to discover a supernova, but this particular supernova has been identified as a different type of stellar explosion. There are two main types of supernova: Type Ia and Type II, both producing powerful explosions.

Credit: Robert E. Moore

Astronomers announced in 2008 that they found a novel explanation for a rare type of super-luminous stellar explosion that may have produced a new type of object known as a quark star. A quark star is a hypothetical type of star composed of ultra dense quark matter. Quarks are the fundamental components of protons and neutrons, which make up the nucleus of atoms.

Credit: NASA/CXC/M.Weiss

A new infrared image has captured the center of our galaxy in never before-seen detail--showing stars and gas swirling into the super massive black hole that lurks at the heart of our own Milky Way.

Credit: Science Nation, National Science Foundation



Stars
Using supercomputers to understand the super stars of the cosmos
Is it a high-speed graphic animation of a yellow-golden cauliflower erupting in fast motion? No. Maybe it's some kind of time-lapse, computer-generated X-ray of a brain as it grows over years. No.

Adam Burrows

It's one of many images Princeton University astrophysicist Adam Burrows has conjured up, using supercomputers to simulate an explosion deep within a star called a supernova. It's not a run-of-the-mill thermonuclear explosion that fuels a healthy star. Instead, it's the kind of explosion that seals a star's fate.

"The rest of the star, its surface, and most of its mass are completely oblivious to its impending fate, but the explosion, which will take just a few seconds, will propagate through the star on periods of hours to a day," explains Burrows.

With help from the National Science Foundation (NSF), Burrows uses supercomputers to create spectacular 3-D images of supernovae that allow him to peer inside these super stars just before they explode.

"One of the things we discovered is that it doesn't explode as a ring expanding out. It explodes in tendrils and fingers, very turbulently," continues Burrows. "The material that's ejected in the supernovae will then start to collapse. Some of that gas will form the next generation of stars and you'll go through the same cycle again."

Supernovae are also the source of many of the heavy elements of nature. In fact, without them, there would be no "us!"

"Some of the heavy elements manufactured in supernovae include the calcium that's in your bones, the fluoride in your toothpaste, and the iron in your blood," says Burrows.

It takes a lot of star power to make those elements. "When supernovae explode, they release the equivalent of 10 to the 28th [or ten octillion] megatons of TNT in energy. One megaton alone is the explosive equivalent of one of the largest hydrogen bombs," Burrows points out.

The computer simulations of supernovae are created using complex mathematical models and take months to process. "Being able to understand the explosions with these simulations is a milestone in theoretical astrophysics," notes Burrows.

Only stars that have about eight times the mass of our sun will die this type of violent death. Burrows says that our sun is a pretty boring star compared to what else is out there.

Miles O'Brien, Science Nation Correspondent
Marsha Walton, Science Nation Producer

The Division of Astronomical Sciences (AST) of the Directorate for Mathematical and Physical Sciences supports research in all areas of astronomy and astrophysics and related multidisciplinary studies.
http://www.nsf.gov/mps/ast/about.jsp

University of California, Berkeley, astronomers have discovered several examples of an unusual type of exploding star that may be a new class of supernovae spewing calcium into the galaxy, which eventually ends up in all of us.
http://www.nsf.gov/news/news_summ.jsp?cntn_id=117025

Astronomers have traced the waxing and waning light of exploding stars more closely than ever before. Using data from the Solar Mass Ejection Imager, a team studied four stars that exploded so violently their light would have been visible without a telescope and measured their brightness over the course of the outburst.
http://www.nsf.gov/news/news_summ.jsp?cntn_id=118223

A giant star in a faraway galaxy recently ended its life with a dust-shrouded whimper instead of the more typical bang.
http://www.nsf.gov/news/news_summ.jsp?cntn_id=117916

A superbright supernova found in a dwarf galaxy by a robotic search is the first confirmed example of a pair-instability supernova.

http://www.nsf.gov/news/news_summ.jsp?cntn_id=116082

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