Subscribe free to our newsletters via your
. 24/7 Space News .




STELLAR CHEMISTRY
Halo of neutrinos alters physics of exploding stars
by Staff Writers
San Diego CA (SPX) Aug 27, 2012


File image.

Sparse halos of neutrinos within the hearts of exploding stars exert a previously unrecognized influence on the physics of the explosion and may alter which elements can be forged by these violent events. John Cherry, a graduate student at UC San Diego, models stellar explosions, including a type called a core-collapse supernova.

As these stars run out of fuel, their cores suddenly collapse to form a neutron star, which quickly rebounds sending seas of neutrinos through the surrounding stellar envelope and out into space.

Even as the collapsed core is rebounding, the rest of the star is still falling inward. Plumes of matter sink, accreting onto the core. "This matter is actually causing some small fraction of neutrinos to bounce at wide angles and cross the trajectories of neutrinos coming from the core," Cherry said.

Astrophysicists knew that the heart of that envelope contained these scattered neutrinos, but because they are relatively few compared with the numbers streaming from the core, they thought their influence on the physics of these explosions would be so minor it could be ignored. Not so, Cherry and colleagues demonstrated in a paper they published in Physics Review Letters. They showed that neutrinos streaming from the core interacted with halo neutrinos far more often than anticipated.

Cherry calculated how often that might occur and how large a difference it would make to their models of neutrinos within supernovae. "What was so startling about this is that nowhere was the correction less than 14 percent. That's enough that you need to worry about it," he said. Indeed, the some places in the outer regions of the envelope require as much as a 10 fold correction.

Neutrinos are famously aloof particles that seldom interact with other matter. "The way neutrinos interact in matter depends on what we call 'flavor'," said George Fuller, professor of physics at UC San Diego who leads the neutrino-modeling research group and is a co-author of the paper.

When neutrinos meet, they "scatter" off one another and in the process can change their flavor. The influence is much greater than physicists thought in the outer halo of neutrinos. "Even though few neutrinos are scattered in funny directions, they can completely dominate how the neutrinos change their favors," Fuller said.

And the balance of neutrino flavors determines many important things."The neutrinos are the engine that drives the exploding star," Cherry said. "What's going on with neutrinos sets the entire stage for what's happening in the explosion."

These stars also forge new elements, and neutrino flavor influences this process as well.

"Those neutrino flavor states allow the neutrinos to change protons to neutrons or neutrons to protons." Cherry said. "What matter is produced, what kinds of atoms, elements are produced by these supernovas are changed dramatically if you change the flavor content of neutrinos."

Joe Carlson and Alexander Friedland of the Los Alamos National Laboratory are co-authors of the work, as is Alexsey Vlasenko of UC San Diego. All authors are also affiliated with (members of?) the New Mexico Consortium's Neutrino Engineering Institute in Los Alamos. The National Science Foundation funded the work at UC San Diego. Work at LANL was supported by the Department of Energy, LANL's internal funding program, and Open Supercomputing.

.


Related Links
University of California - San Diego
Stellar Chemistry, The Universe And All Within It






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





STELLAR CHEMISTRY
Astronomy project hunts for Chinese helpers
Beijing, China (XNA) Aug 24, 2012
The online astronomy project - Galaxy Zoo - is searching for Chinese people to help categorize galaxies in the universe. The Zoo, which has no animals but more than one million galaxies, was set up in 2007 by a group of astronomers who found it impossible to classify the numerous galaxies. So they turned to the public and are now seeking help from the Chinese. "I hope Chinese people will l ... read more


STELLAR CHEMISTRY
Neil Armstrong: First man on the moon

US astronaut Neil Armstrong dead at 82

Obama hails 'great American hero' Neil Armstrong

Chinese firm to send Spanish rover to moon in 2014

STELLAR CHEMISTRY
Chemcam Laser First Analyzes Yield Beautiful Results

NASA's Mars rover makes first test drive

First Words of Safe Landing on Mars - Tango Delta Nominal

NASA Mars Rover Begins Driving at Bradbury Landing

STELLAR CHEMISTRY
Singer Sarah Brightman could be next space tourist: report

Sarah Brightman In Talks Over Space Trip

For US students, plane tickets, TVs are relics

Voyager at 35: Break on Through to the Other Side

STELLAR CHEMISTRY
China unveils ambitious space projects

Is China Going to Blast Past America in Space?

Hong Kong people share joy of China's manned space program

China's Long March-5 carrier rocket engine undergoes testing

STELLAR CHEMISTRY
Europe's ATV-3 Space Freighter Raises ISS Orbit to 420 km

Russia's ISS Crew Members Complete Spacewalk

Sierra Nevada Supports Communications Experiment on ISS

Space station orbit successfully adjusted

STELLAR CHEMISTRY
ASTRA 2F touches down in French Guiana for Arianespace's next Ariane 5 dual-passenger mission

Satellite preparations move into full swing for the next Arianespace Soyuz mission from French Guiana

Russian Booster Rocket Lifts US Satellite in Seaborne Launch

India's GSAT-10 satellite continues its checkout for the upcoming Arianespace Ariane 5 mission

STELLAR CHEMISTRY
First Evidence Discovered of Planet's Destruction by Its Star

Exoplanet hosting stars give further insights on planet formation

Five Potential Habitable Exoplanets Now

RIT Leads Development of Next-generation Infrared Detectors

STELLAR CHEMISTRY
New catalyst could improve production of glass alternatives

China to expand rare earths reserves: report

Elusive metal discovered

Northwestern scientists create chemical brain




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement