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


Subscribe free to our newsletters via your




















First X-Ray Detection Of A Colliding-Wind Binary Beyond Milky Way

A Hubble Space Telescope view of the cluster NGC 346 - the arrow indicates the position of HD 5980. Credits: NASA, ESA, A. Nota (STScI/ESA)
by Staff Writers
Paris, France (ESA) Feb 23, 2007
Imagine two stars with winds so intense that they eject an Earth's worth of material roughly once every month. Next, imagine those two winds colliding head-on. Such titanic collisions produce multimillion-degree gas, which radiates brilliantly in X-rays. Astronomers have conclusively identified the X-rays from about two-dozen of these systems in our Milky Way. But they have never seen one outside our galaxy - until now.

Thanks to the European Space Agency's XMM-Newton X-ray observatory, with help from NASA's Chandra X-ray Observatory, an international team led by Dr. Yael Naze of the Universite de Liege in Belgium has found such a system in the Small Magellanic Cloud, a dwarf galaxy located about 170,000 light-years from Earth.

The binary star system, known as HD 5980, contains two stars "weighing" about 50 and 30 times the mass of our Sun. Each star radiates more than a million times as much light as the Sun. The sheer photon pressure of this incredible outpouring of light blows off gas from each star in a "wind" that is 5 times faster than the solar wind. Each star's rate of mass loss is about 10 billion times greater than the solar wind.

HD 5980's two stars are separated by only about 56 million miles (90 million kilometers), roughly half Earth's average distance from the Sun. With such close proximity, the winds smash into each other with tremendous force, heating the gas and generating enormous numbers of X-rays. The system emits about 10 times more energy in X-rays alone than the Sun radiates over the entire spectrum.

Using data from Chandra, the same team first reported HD 5980's highly energetic X-ray emission in 2002. But its origin was uncertain. Data taken from 2000 to 2005 with XMM-Newton shows that it is indeed produced by a wind collision. The stars orbit each other every 20 days in a plane that is edge-on to Earth's line of sight, so the stars periodically eclipse each other. The wind collision is thus seen from different angles and through different amounts of material. XMM-Newton saw the X-ray emission rise and fall in a repeating, predictable pattern.

"Similar X-ray variability from massive binaries inside the Milky Way has been detected, but this is the first indisputable evidence for the phenomenon outside our galaxy," says Naze. "This discovery highlights the great capabilities of modern X-ray observatories."

XMM-Newton has the largest mirrors of any X-ray observatory ever flown, which enabled astronomers to monitor this distant system. HD 5980 itself is embedded inside hot interstellar material that creates a diffuse X-ray glow that makes the object difficult to study. Chandra data enabled the scientists to pinpoint HD 5980 and resolve the system from the diffuse emission.

HD 5980 is one of the Small Magellanic Cloud's brightest stars. Situated on the periphery of the star cluster NGC 346, the two stars are nearing the end of their lives and will eventually explode as supernovae.

"Colliding winds provide an important handle on how massive stars shed material," says team member Dr. Michael F. Corcoran, a scientist with the Universities Space Research Association at NASA's Goddard Space Flight Center in Greenbelt, Md. "Being able to study them in external galaxies means we can study the effects of different compositions and environments on how these massive stars evolve. From the XMM-Newton data, we can study the delicate balance between the two winds, and determine the changing strength of the winds."

The team's paper has been accepted for publication in The Astrophysical Journal Letters. Coauthors include Dr. Gloria Koenigsberger of the Universidad Nacional Autonoma de Mexico and Dr. Anthony J. Moffat of the Universite de Montreal in Canada. For more information, visit the ESA press release website.

Email This Article

Related Links
ESA's XMM-Newton satellite
NASA's Chandra X-ray Observatory
Stellar Chemistry, The Universe And All Within It



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


New Observations Show Sun-Like Star In Earliest Stage Of Development
Boulder CO (SPX) Feb 23, 2007
Members of a research team led by the University of Colorado at Boulder have used NASA's Chandra X-ray Observatory to peer at the embryo of an infant star in the nearby Eagle Nebula, which they believe may someday develop into a virtual twin of Earth's sun. The object, known as an evaporating gas globule, or EGG, has the same mass as the sun and appears to be evolving in a violent environment much like the one believed to have produced Earth's sun, said researcher Jeffrey Linsky of JILA, a joint institute of CU-Boulder and the National Institute of Standards and Technology.







  • Astronauts Urged To Take Up Skiing Ahead Of Lunar Missions
  • Speeding To Zeus On Route Pluto
  • Space Radiation Could Be A Mars Mission-Killer
  • Detecting Radiation On Lunar And Mars Missions

  • Opportunity Continues To Characterize Crater
  • Are Human Beings The Biggest Risk Factor In Long-Term Space Missions
  • APL-Built Mineral Mapper Uncovering Clues Of Martian Surface Composition
  • Spirit Perfects The Art Of Driving On Five Wheels

  • SERVIS-2 To Be Launched On Rockot
  • Russia Space Agency Hopes Sea Launch Will Resume Operation In 2007
  • United Launch Alliance First East Coast Launch A Total Success
  • Arianespace And Astrium Sign Agreement On Ariane 5 Production Increase

  • Sandstorm Over The Mediterranean
  • 3D Upstart Eyes Google Earth With Helicopter
  • ESA Celebrates 15 Years Of Near-Real Time Data Delivery In Earth Observation
  • Gascom To Launch 4 Smotr Low-Orbit Remote Sensing Satellites

  • All Calm On Approach To Jupiter For Flyby
  • New Horizons SWAP Instrument Observes Solar Wind Interactions Before Jupiter Encounter
  • One Year Down, Eight to Go, On The Road to Pluto
  • NASA Spacecraft En Route To Pluto Prepares For Jupiter Encounter

  • New Observations Show Sun-Like Star In Earliest Stage Of Development
  • First X-Ray Detection Of A Colliding-Wind Binary Beyond Milky Way
  • Spitzer First to Crack Open Light of Faraway Worlds
  • Peering Into The Pillars Of Creation

  • Out-Of-This-World Ride In NASA's 14th Annual Great Moonbuggy Race
  • Why Are We Fighting For The Moon Again
  • AIAA Recommends Actions For Implementation Of Lunar Settlements
  • The Moon Is A School For Exploration

  • GPS Upgrade Will Require Complicated Choreography
  • China Puts New Navigation Satellite Into Orbit
  • Port Of Rotterdam To Use SAVI Networks Savitrak For Cargo Security And Management Service
  • GMV Signs Galileo Contracts Worth Over 40 Million Euros

  • 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