Posted on 01/06/2007 11:43:11 PM PST by NormsRevenge
PARIS (AFP) - Astronomers in Europe and the United States have detected the remnants of two exploding stars that could lead to a rethink about supernovae, the European Space Agency said.
The team examined X-ray data from the embers of two supernovae, DEM L238 and DEM L249, which were stars that had exploded in a nearby galaxy.
Most supernovae occur when a very massive star runs out of fuel, its core collapses and then explodes, leaving behind a neutron star or a black hole.
But there is also a rarer supernova, called Type 1a, which starts with a binary system of two stars that rotate around each other.
One is a so-called white dwarf -- the tiny, extremely hot, very dense core of an old star -- and the other is a "red giant," a cooling, ageing star that is running out fuel.
The theory is that mass flows from the red giant to the white dwarf, which eventually collapses in on itself and explodes in a massive thermonuclear blast.
DEM L238 and DEM L249 both showed high concentrations of iron atoms, a classic Type 1a signature, the ESA statement said.
But the hot gas emitted from their remnants was far denser and brighter in the X-ray part of the energy spectrum than for typical Type 1a blasts.
The astronomers suggest that a new class of supernovae may exist -- a supernova that evolves in the style of the Type 1a, but lives and dies much more swiftly, driven by the creation of an exceptionally massive white dwarf.
"We know that the more massive a star is, the shorter its lifetime," ESA quoted Kazimierz Borkowski of North Carolina State University as saying.
"If such a star could also begin to pull matter from its companion at an early stage, then this star would have a much shorter fuse and explode in only about 100 million years, much less than other Type 1a supernovas."
The evidence for the fast-track supernovae comes from ESA's XMM-Newton and NASA's Chandra X-ray orbital observatories.
This NASA Hubble Space Telescope image released 07 February, 2006 shows spiral galaxy NGC 1309, home to supernova SN 2002fk. Astronomers in Europe and the United States have detected the remnants of two exploding stars that could lead to a rethink about supernovae, the European Space Agency said.(AFP/NASA-HO/File)
some more pics of DEM L238 and DEM L249 at Chandra X-Ray site,, too big to post on the thread. check them out.
link to Chandra X-Ray pagewith images
http://chandra.harvard.edu/photo/2007/deml238/more.html#deml238_xray_opt
Very cool link!
Supernova debris found on Earth
news@nature.com | 02 November 2004 | Mark Peplow
Posted on 11/24/2004 1:22:08 PM PST by Phsstpok
http://www.freerepublic.com/focus/news/1287848/posts
The Cycle of Cosmic Catastrophes:
Flood, Fire, and Famine
in the History of Civilization
by Richard Firestone,
Allen West, and
Simon Warwick-Smith
 |
||
| · join · view topics · view or post blog · bookmark · post new topic · | ||
 |
||
| · join · view topics · view or post blog · bookmark · post new topic · | ||
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.
