European Association for Astronomy Education

Source: NRAO

Core-collapse supernova explosion
expelling nearly-spherical debris shell.
CREDIT: Bill Saxton, NRAO/AUI/NSF

For the first time, astronomers have found a supernova explosion with properties similiar to a gamma-ray burst, but without seeing any gamma rays from it. The discovery, using the National Science Foundation’s Very Large Array (VLA) radio telescope, promises, the scientists say, to point the way toward locating many more examples of these mysterious explosions.

“We think that radio observations will soon be a more powerful tool for finding this kind of supernova in the nearby Universe than gamma-ray satellites,” said Alicia Soderberg, of the Harvard-Smithsonian Center for Astrophysics.

The telltale clue came when the radio observations showed material expelled from the supernova explosion, dubbed SN2009bb, at speeds approaching that of light. This characterized the supernova, first seen last March, as the type thought to produce one kind of gamma-ray burst. (read more)

Credit: Max-Planck-Institute für Astrophysik

Astronomers at the Max-Planck-Institute for Astrophysics in Garching have used computer simulations to confirm that some supernovae are due to the merger of two white dwarfs. White dwarfs are compact remnants of extinguished solar-type stars. As supernovae are used by astronomers to measure cosmic distances and study the expansion history of our Universe, understanding their mechanism is one of the key challenges in astrophysics. This article was published on Nature, 7. January 2010. (read more)

Original publication:
Rüdiger Pakmor, Markus Kromer, Friedrich K. Röpke, Stuart A.Sim, Ashley J. Ruiter, Wolfgang Hillebrandt, “Sub-luminous type Ia supernovae from the mergers of equal-mass white dwarfs with M~0.9 M_solar”, Nature, 7. January 2010 (view online, requires subscription)

Links:

Website of the linkPfeil.gifsupernova research group
Computer simulation of two merging white dwarfs ( linkPfeil.gifMPEG4 Format , linkPfeil.gifMPEG1 Format )

Source:NASA Science News

A supercomputer model of a rapidly-spinning, core-collapse supernova.
Credit: Fiona Harrison/Caltech.

A massive old star is about to die a spectacular death. As its nuclear fuel runs out, it begins to collapse under its own tremendous weight. The crushing pressure inside the star skyrockets, triggering new nuclear reactions, setting the stage for a terrifying blast. And then… nothing happens.

At least that’s what supercomputers have been telling astrophysicists for decades. Many of the best computer models of supernova explosions fail to produce an explosion. Instead, according to the simulations, gravity wins the day and the star simply collapses. (read more)

Source: SPACE.com

Kepler’s Supernova. Credit: NASA/ESA/JHU/R.Sankrit & W.Blair

The star T Pyxidis, which lies over 3,000 light-years away from the Earth in the constellation Pyxis, was previously thought to be far enough away that if anything happened in the way of a supernova, we’d be pretty safe. According to Edward Sion, Professor of Astronomy and Physics at Villanova University, T Pyxidis may be in fact a “ticking time bomb,” and potential threat to the Earth if it were to go supernova, which it may do sometime in the future, though very, very far in the future on our timescale: by Scion’s calculations, at least 10 million years.(read more)

Related Links:
Universe Today
Space Daily

Source: Berkeley Lab

Astronomers from the University of California Berkeley have analyzed the explosion, which was recorded by a robotic survey in 2007, and found that it is likely the first confirmed observation ever made of a pair-instability supernova, a type of extremely energetic supernova that has been theorized but never directly confirmed.(Read more)

Image source: Weizmann Institute of Science

Related Links: Universe Today