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




STELLAR CHEMISTRY
XMM-Newton Uncovers A Celestial Rosetta Stone
by Staff Writers
Paris, France (ESA) Sep 04, 2009


File image: White dwarf.

ESA's XMM-Newton orbiting X-ray telescope has uncovered a celestial Rosetta stone: the first close-up of a white dwarf star, circling a companion star, that could explode into a particular kind of supernova in a few million years. These supernovae are used as beacons to measure cosmic distances and ultimately understand the expansion of our Universe.

Astronomers have been on the trail of this mysterious object since 1997 when they discovered that something was giving off X-rays near the bright star HD 49798. Now, thanks to XMM-Newton's superior sensitivity, the mysterious object has been tracked along its orbit. The observation has shown it to be a white dwarf, the dead heart of a star, shining X-rays into space.

Sandro Mereghetti, INAF-IASF Milan, Italy, and collaborators also discovered that this is no ordinary white dwarf. They measured its mass and found it to be more than twice what they were expecting. Most white dwarfs pack 0.6 solar masses into an object the size of Earth.

This particular white dwarf contains at least double that mass but has a diameter just half that of Earth. It also rotates once every 13 seconds, the fastest of any known white dwarf.

The mass determination is reliable because the XMM-Newton tracking data allowed the astronomers to use the most robust method for 'weighing' a star, one that uses the gravitational physics devised by Isaac Newton in the 17th century. Most likely, the white dwarf has grown to its unusual mass by stealing gas from its companion star, a process known as accretion. At 1.3 solar masses, the white dwarf is now close to a dangerous limit.

When it grows larger than 1.4 solar masses, a white dwarf is thought to either explode, or collapse to form an even more compact object called a neutron star.

The explosion of a white dwarf is the leading explanation for type Ia supernovae, bright events that are used as standard beacons by astronomers to measure the expansion of the Universe. Until now, astronomers have not been able to find an accreting white dwarf in a binary system where the mass could be determined so accurately.

"This is the Rosetta stone of white dwarfs in binary systems. Our precise determination of the masses of the two stars is crucial. We can now study it further and try to reconstruct its past, so that we can calculate its future," says Mereghetti.

That future is a spectacular one. The star is likely to explode in a few million years' time. Although it is far enough to pose no danger to Earth, it is close enough to become an extraordinarily spectacular celestial sight. Calculations suggest that it will blaze initially with the intensity of the full moon and be so bright that it will be seen in the daytime sky with the naked eye.

Our descendants are in for quite a show. Thanks to XMM-Newton, we can already start looking forward to it.

'An ultra massive fast-spinning white dwarf in a peculiar binary system' by S Mereghetti, A Tiengo, P Esposito, N La Palombara, GL Israel, L. Stella will be published in Science on 4 September 2009.

.


Related Links
XMM-Newton
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
Researchers Show Component Of Mothballs Is Present In Deep-Space Clouds
Athens GA (SPX) Sep 03, 2009
Interstellar clouds, drifting through the unimaginable vastness of space, may be the stuff dreams are made of. But it turns out there's an unexpectedly strange component in those clouds, and it's not dreams but-mothballs? Well, not exactly, but researchers from the University of Georgia have just shown for the first time that one component of clouds emitting unusual infrared light know as ... read more


STELLAR CHEMISTRY
Indian satellite confirmed US moon landing: scientist

Chandrayan I Mission Failure Setback For India

Indian scientists hail aborted lunar mission a success

India suffers blow to space ambitions

STELLAR CHEMISTRY
Thousands Of New Images Show Mars In High Resolution

Amase-ing Life On The Ice

Opportunity Continues Meteorite Examination - Sol 1981-1987

Mars Orbiter Puts Itself In Safe Mode Again

STELLAR CHEMISTRY
New Class Of European Astronauts Report For Training

Lockheed Martin Says Orion Is Go For CDR

NASA Partners To Revolutionize Personal Transportation

The future first clown in space to advocate for water

STELLAR CHEMISTRY
Rocket Hiccup No Jam-Up For China

China To Begin Construction Of Orbital Space Station In 2020

Russia launches China communications satellite: report

China Conducts Stringent Tests Of Would-Be Spacemen

STELLAR CHEMISTRY
NASA monitors space junk ahead of spacewalk

MISSE-6 Comes Home After More Than a Year in Space

ESA Astronaut Answers Your Questions From Space

Astronauts install coolant tank at space station

STELLAR CHEMISTRY
Arianespace Pre-Launch Processing Of Amazonas 2 Underway

China-Launched Indonesian Satellite Fails To Enter Orbit

TURKSAT 4A Satellite To Be Launched To Space In 2011

Amazonas 2 Is Delivered To The Spaceport

STELLAR CHEMISTRY
Scientists wonder about planet's location

A Look Into The Hellish Cradles Of Suns And Solar Systems

New Planet Orbits Backwards

Huge New Planet Tells Of Game Of Planetary Billiards

STELLAR CHEMISTRY
Reno Researcher Uses 100,000 Degree Heat To Study Plasma

Sony throws down the 3D gauntlet with new TV

Palapa D In Normal State After Failure To Enter Orbit

Space Sciences Lab Celebrates 50 Years And 75 satellites




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