. 24/7 Space News .
Tycho's Remnant Provides Shocking Evidence For Cosmic Rays

Chandra X-ray Image of Tycho's Supernova Remnant. Credit: NASA/CXC/Rutgers/J.Warren & J.Hughes et al. See larger image.

Boston MD (SPX) Sep 23, 2005
Astronomers have found compelling evidence that a supernova shock wave has produced a large amount of cosmic rays, particles of mysterious origin that constantly bombard the Earth. This discovery, made with NASA's Chandra X-ray Observatory, supports theoretical arguments that shock waves from stellar explosions may be a primary source of cosmic rays.

This finding is important for understanding the origin of cosmic rays, which are atomic nuclei that strike the Earth's atmosphere with very high energies. Scientists believe that some are produced by flares on the Sun, and others by similar events on other stars, or pulsars or black hole accretion disks.

But, one of the prime suspects has been supernova shock waves. Now, a team of astronomers has used Chandra observations of Tycho's supernova remnant to strengthen the case for this explanation.

"With only a single object involved we can't state with confidence that supernova shock waves are the primary source of cosmic rays," said John

P. Hughes of Rutgers University in Piscataway, New Jersey, and coauthor of a report to be published in an upcoming issue of The Astrophysical Journal. "What we have done is present solid evidence that the shock wave in at least one supernova remnant has accelerated nuclei to cosmic ray energies."

In the year 1572, the Danish astronomer Tycho Brahe observed and studied the sudden appearance of a bright "new star" in the constellation Cassiopeia. Now known as Tycho's supernova remnant, the event created a sensation in Tycho's time because it exploded the myth that stars never change.

Four centuries later, the Chandra results on Tycho's remnant show that some modern ideas of the aftermath of supernova explosions may have to be revised. The report by Hughes and colleagues demonstrates that the shock wave produced by the explosive disruption of the star behaves in a way that cannot be explained by the standard theory.

The supernova debris is observed to expand at a speed of about six million miles per hour. This rapid expansion has created two X-ray emitting shock waves - one moving outward into the interstellar gas, and another moving inward into the stellar debris.

These shock waves, analogous to the sonic boom produced by supersonic motion of an airplanes, produce sudden, large changes in pressure, and temperature behind the wave.

According to the standard theory, the outward-moving shock should be about two light-years ahead of the stellar debris (that's half the distance from our sun to the nearest star). What Chandra found instead is that the stellar debris has kept pace with the outer shock and is only about half a light-year behind.

"The most likely explanation for this behavior is that a large fraction of the energy of the outward-moving shock wave is going into the acceleration of atomic nuclei to speeds approaching the speed of light," said Jessica Warren, also of Rutgers University, and the lead author of the report in the Astrophysical Journal.

Previous observations with radio and X-ray telescopes had established that the shock wave in Tycho's remnant was accelerating electrons to high energies. However, since high-speed atomic nuclei produce very weak radio and X-ray emission also, it was not known whether the shock wave was accelerating nuclei as well.

The Chandra observations provide the strongest evidence yet that nuclei are indeed accelerated, and that the energy contained in high-speed nuclei is about 100 times that in the electrons.

Hughes also pointed out that the Chandra result for Tycho's remnant significantly changes astronomers' view of the evolution of supernova remnants. A large component of cosmic ray nuclei alters the dynamics of the shock wave, and may require changing the way that astronomers estimate the explosive energy of a supernova from the properties of its remnant.

NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency's Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.

Related Links
Chandra at Harvard
SpaceDaily
Search SpaceDaily
Subscribe To SpaceDaily Express



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


Case Astronomers Find Vast Stellar Web Spun By Colliding Galaxies
Cleveland OH (SPX) Sep 22, 2005
Case Western Reserve University astronomers have captured the deepest wide-field image ever of the nearby Virgo cluster of galaxies, directly revealing for the first time a vast, complex web of "intracluster starlight" - nearly 1,000 times fainter than the dark night sky - filling the space between the galaxies within the cluster.







  • Final Call For Applicants For Space Exploration Masters
  • Aeronautics And Space Funding Will Preserve U.S. Aerospace Leadership
  • World's Third Space Tourist Ready For Journey
  • A September Surprise For China's Second Manned Launch - Shenzhou 6

  • Mars Express Mission extended
  • WUSTL Mars Team Describes Water Detection At Gusev Crater
  • Mars Doubles In Brightness
  • Orbiter's Long Life Helps Scientists Track Changes On Mars

  • Boeing And Lockheed Martin To Resubmit Filing For United Launch Alliance
  • Orbital Selected By NASA For Major Long-Term Launch Services Contract
  • NASA Awards Launch Services Contract To Orbital Sciences
  • Russia Launches Canadian Satellite

  • Orbimage Announces Awards Totaling $6.1M Of ClearView Orders From The NGA
  • NASA Technology Monitors Wildlife Habitats From The Air
  • NASA Cooperative Airborne Laser Mapping Studies Katrina Damage
  • Envisat Sensors Measuring Heat And Light

  • Santa et al
  • Hubble Makes Movie Of Neptune's Dynamic Atmosphere
  • Gemini Samples Spectrum Of 2003 UB313: Pluto-Like Surface
  • Scientists Discover Tenth Planet

  • Tycho's Remnant Provides Shocking Evidence For Cosmic Rays
  • Double Star And Cluster Observe First Evidence Of Crustal Cracking
  • Case Astronomers Find Vast Stellar Web Spun By Colliding Galaxies
  • New Star Survey Sheds Light On Milky Way's Evolution

  • Not Your Average Moonshot
  • Digging "Moon Dirt" Is NASA's Fifth Centennial Challenge
  • With Moon Mission, US Seeks To Remain Leader In Space
  • How We'll Get Back To The Moon

  • Chinese Company Bids For Galileo Operation Franchise
  • Harris Offer Low-Cost Weapon Data Link Used In JDAM Moving Target Demo
  • Lost In Shanghai? Your Map Is Counterfeit
  • 2-Track Global Announces Successful Testing Of Starfish Product

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights 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 SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement