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Posted on 04/07/2003 4:18:51 PM PDT by vannrox
It's A Nova ? It's A Supernova ? It's A HYPERNOVA
ANN ARBOR, Mich. --- Two billion years ago, in a far-away galaxy, a giant star exploded, releasing almost unbelievable amounts of energy as it collapsed to a black hole. The light from that explosion finally reached Earth at 6:37 a.m. EST on March 29, igniting a frenzy of activity among astronomers worldwide. This phenomenon has been called a hypernova, playing on the name of the supernova events that mark the violent end of massive stars.
With two telescopes separated by about 110 degrees longitude, the Robotic Optical Transient Search Experiment (ROTSE) will have one of the most continuous records of this explosion.
"The optical brightness of this gamma ray burst is about 100 times more intense than anything we've ever seen before. It's also much closer to us than all other observed bursts so we can study it in considerably more detail," said Carl W. Akerlof, an astrophysicist in the Physics Department at the University of Michigan. Akerlof is the leader of ROTSE, an international collaboration of astrophysicists using a network of telescopes specially designed to capture just this sort of event. The collaboration is headquartered at U-M and funded by NASA and the National Science Foundation (NSF).
Just recently, the ROTSE group commissioned two optical telescopes in Australia and Texas and were waiting for the first opportunities to use the new equipment. The burst was promptly detected by NASA's Earth orbiting High-Energy Transient Explorer (HETE-2) but human intervention was required to find the exact location.
Despite sporadic clouds and rainstorms in Australia, the ROTSE instrument at Siding Spring Observatory in northern New South Wales was able to record the decaying light from the blast. Twelve hours later, the second ROTSE telescope in Fort Davis, Texas was picking up the job of monitoring this spectacular explosion.
"During the first minute after the explosion it emitted energy at a rate more than a million times the combined output of all the stars in the Milky Way. If you concentrated all the energy that the sun will put out over its entire 9 billion-year life into a tenth of a second, then you would have some idea of the brightness," said Michael Ashley, faculty member in the astrophysics and optics department at the University of New South Wales and a member of the ROTSE team.
Akerlof became interested in studying gamma ray bursts in the early 1990s. While they are the most powerful explosions in the universe, gamma-ray bursts are extremely hard to study because they are extremely distant, occur randomly in time and seldom last more than a minute. Small, fast, and relatively inexpensive robotic ground-based telescopes like ROTSE offer the best chance of catching early optical emissions from the bursts. ROTSE attracted national notice in 1999 when it captured the rise and fall of GRB990123, one of the brightest bursts prior to this latest event.
"The ROTSE equipment is quite modest by modern standards, but its wide field of view and fast response allow it to make measurements that more conventional instruments cannot," Akerlof said. "We have two telescopes online now, and installations in Namibia and Turkey will follow soon. Our goal is to have telescopes continuously trained on the night sky. Our motto is "The Sun never rises on the ROTSE array." That's why we want them spread as widely as possible."
Another role for ROTSE and other small telescopes is to alert larger facilities about gamma ray bursts and other transient phenomena. "One of the most exciting things about an event like this is the way the global community of scientists pulls together, pooling their data and their different capabilities," Akerlof said.
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For more information about ROTSE, visit http://www.rotse.net. To learn more about physics at the U-M visit http://www.physics.lsa.umich.edu. For more about Carl Akerlof, see
http://www.physics.lsa.umich.edu/department/directory/bio.asp?ID=5.
Editor's Note: The original news release can be found here.
Note: This story has been adapted from a news release issued for journalists and other members of the public. If you wish to quote any part of this story, please credit University Of Michigan as the original source. You may also wish to include the following link in any citation:
http://www.sciencedaily.com/releases/2003/04/030407075127.htm
Impressive Output Indeed!
I hope our poles don't flip!
Feh. I've seen bigger. </sarcasm>
Awesome amount of energy!
Is there a known physical process to explain this kind of output?
It's the same word, the same root. super = ekshyper, Gr., above.
If they want to play the great, monster, giant, excessively huge word game, they could go to international standard --IS-- prefices, all of whch are Greek. Excessivly huge would be exanova. Beyond that would be zetanova, 1000 times more impressive than an exanova, or yottanova, 1000 times more impressive than zetanova. If they need to exaggerate further, there is the Arabic language waiting in the wings.
Yet, even these are subservient to the bossa nova!
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You ever been to Donnybrooke? I think that's what they called the race track near Brainerd, Minnesota.
From SPACE.com, 28 sept 2000 .. J Craig Wheeler
I have been working in the field of
We have known since the 30's that supernovae light up in distant galaxies, representing enough energy release to tear a star asunder. There are two very broad categories -- those that represent the thermonuclear explosion of a white dwarf and those that represent the collapse inward and subsequent explosion outward of an aged stellar core.
Images
Gamma rays are imbedded in stellar winds emitted by exploding stars.
Chandra's image of supernova remnant G21.5-0.9. At both radio and x-ray wavelengths, this relic of a supernova blast appears as a round patch in the sky.
More Stories
Most Distant Novae Ever Spotted by Chilean Observatory
Hubble Detects Gamma Ray Burst, Possible Parent Supernova
Chandra Captures Heavy Metal Expulsion from Supernova
Possible Hypernova Could Affect Earth
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Hubble image of Supernova 1987-A shows bright features as of February 2, 2000 (left) compared with the early days of the developing ring in 1997. |
The first is like a stick of dynamite and leaves nothing behind. The second involves the formation of a compact star, a
neutron star or a black hole. Interestingly, both of these processes appear to eject the same amount of kinetic energy -- the energy of mass motion -- into space. For the thermonuclear process that is essentially all the energy. For the collapse process, a hundred times more energy is liberated in total, but that extra comes out in ephemeral neutrinos, not in the exploding energy of ordinary matter.The hypernovae have brought in a surprising new perspective. The term "hypernova" has a confused etymological history and means different things to different astrophysicists. Bohdan Paczynski of Princeton University used it to refer to the very bright events associated with the newly discovered optical counterparts to cosmic
gamma-ray bursts. These are much brighter than supernovae. Then supernova researchers used it to describe Supernova 1998-bw. This event is strongly suspected to have been the source of a gamma-ray burst, but one very nearby in gamma-ray burst terms, only 120 million light-years, not the billions of light-years we have learned are typical.The association of the supernova with the gamma-ray burst is still controversial. With the supernova community being ardent believers since the supernova was so weird, and some members of the gamma-ray burst community retaining suspicions since a burst this close would have to be of unusually low energy. The supernova is, undoubtedly, odd. It was exceptionally bright for a supernova. It was a very powerful source of radio radiation requiring expansion of a shock wave at nearly the speed of light, and its spectral features revealed very high velocities compared to "normal" supernovae.
Several groups of researchers made models of this event. Making the standard assumption that the supernova blew up equally vigorously in all directions, these models suggested that Supernova 1998-bw had an expansion energy of matter that was over 10 times that of normal supernovae. That became a new operational definition of a "hypernova."
A handful of other supernovae have been identified that also seem to require very high energy if we assume the explosions exerted equal force in all directions, by dint of being very bright events with very high expansion speeds. These were also only recently discovered in the last two or three years. Where were these very bright, very noticeable, supernovae for the first 30 years of my career?
This is a rich area with many lines of thought to be explored. A critical one is whether the hypernovae, or any supernova for that matter, actually does expand outward equally in all directions. The answer is that normal supernovae, at least those associated with collapsing stars, do not. They tend to blow matter out faster along two opposing directions rather than in other directions. They might also tend to be brighter in that direction.
It is possible that the "hypernovae" are just "normal" core-collapse supernovae, but seen from a special angle? The majority opinion is that hypernovae really are different. The question then arises as to how and why. Do they represent black-hole, rather than neutron-star formation? Do they represent neutron-star formation of a special kind, say with an extra-strong magnetic field or extra-fast rotation? Are they related to gamma-ray bursts of some kind?
These are the sorts of issues that keep a scientist in constant overdrive.
Dr. J. Craig Wheeler is the author of Cosmic Catastrophes: Supernovae, Gamma-Ray Bursts, and Adventures in Hyperspace, and is the Samuel T. and Fern Yanagisawa Regents Professor of Astronomy, at The University of Texas at Austin. His course "Astronomy Bizarre" specializes in the weirder aspects of space science for non-science majors.
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