Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. 24/7 Space News .




STELLAR CHEMISTRY
Massive stellar winds are made of tiny pieces
by Staff Writers
Paris (ESA) Feb 06, 2013


Artist's impression comparing a smooth stellar wind (left) with a highly fragmented stellar wind (right) of a massive star like zeta Puppis. A decade's-worth of observations with ESA's XMM-Newton have revealed that the wind of zeta Puppis is fragmented into hundreds of thousands of individual hot (red) and cool (blue) clumps. Studying stellar winds is vital not only to understand mass loss from the star itself and thus its expected lifetime, but also how the winds inject material and energy into the surrounding environment and influence the birth and death of other stars. Copyright ESA-C. Carreau/Naze et al.

ESA's XMM-Newton space observatory has completed the most detailed study ever of the fierce wind from a giant star, showing for the first time that it is not a uniform breeze but is fragmented into hundreds of thousands of pieces. Massive stars are relatively rare, but play a very important role in recycling materials in the Universe.

They burn their nuclear fuel much more rapidly than stars like the Sun, living only for millions of years before exploding as a supernova and returning most of their matter to space.

But even during their brief lives, they lose a significant fraction of their mass through fierce winds of gas driven off their surfaces by the intense light emitted from the star.

The winds from massive stars are at least a hundred million times stronger than the solar wind emitted by our own Sun and can significantly shape their surrounding environment.

They might trigger the collapse of surrounding clouds of gas and dust to form new stars or, conversely, blast the clouds away before they have the chance to get started.

Despite their important role, however, the detailed structure of the winds from massive stars remains poorly understood. Are they steady and uniform, or broken up and gusty?

Astronomers have now gained a detailed glimpse into this wind structure by taking observations with XMM-Newton spread over a decade to study variability in the X-ray emission from zeta Puppis. One of the nearest massive stars to Earth, it is bright enough to be seen with the naked eye in the constellation of Puppis, in the southern hemisphere.

The X-rays arise from collisions between slow- and fast-moving clumps in the wind, which heats them to a few million degrees. As individual colliding clumps in the wind are heated and cooled, the strength and energy of the emitted X-rays vary.

If only a small number of large fragments are present, variations in the combined emission could be large. Conversely, as the number of fragments grows, a change in the X-ray emission from any given fragment becomes less important, and the overall variability decreases.

In zeta Puppis, the X-ray emission was found to be remarkably stable over short timescales of just a few hours, pointing to a very large number of fragments. There must still be clumps in the wind to make X-rays in the first place, but there must be many of them to yield such low variability.

However, unexpected variation in the emission was seen on the order of several days, implying the presence of a few very large structures in the wind, possibly spiral-arm-like features superimposed on the highly fragmented wind co-rotating with the star.

"Studies at other wavelengths had already hinted that the winds from massive stars are not simply a uniform breeze, and the new XMM-Newton data confirm this, but also reveal hundreds of thousands of individual hot and cool pieces," says Yael Naze, Universite de Liege, Belgium, who led the study's analysis.

"This is the first time constraints have been placed on the number of fragments in a stellar wind of an adult massive star, a number which far exceeds theoretical predictions."

To fully understand these observations, improved models of stellar winds will be needed, taking into account both the large-scale emission structures and the highly fragmented wind, in order to understand how they affect mass-loss in stellar giants.

"Zeta Puppis also goes by the name Naos, which in antiquity was the name given to the innermost sanctuary of a temple, accessible to only a few people; thanks to XMM-Newton, scientists have been able to unlock the secrets of this mysterious stellar object," adds Dr Naze.

"This long-term XMM-Newton study of zeta Puppis has provided the first constraints on the number of fragments in a stellar wind from a massive star - there is no dataset with comparable sensitivity or time and or spectral coverage currently available for any other massive star," says Norbert Schartel, ESA's XMM-Newton project scientist.

.


Related Links
XMM-Newton overview
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
Where are all the dwarfs?
Potsdam, Germany (SPX) Feb 05, 2013
Astronomers of the international CLUES collaboration have identified "Cosmic Web Stripping" as a new way of explaining the famous missing dwarf problem: the lack of observed dwarf galaxies compared with that predicted by the theory of Cold Dark Matter and Dark Energy. High-precision observations over the last two decades have indicated that our Universe consists of about 75% Dark Energy, 2 ... read more


STELLAR CHEMISTRY
Building a lunar base with 3D printing

US, Europe team up for moon fly-by

Russia to Launch Lunar Mission in 2015

US, Europe team up for moon fly-by

STELLAR CHEMISTRY
Mapping Mars

Weekend Test on Mars Was Preparation to Drill a Rock

AAS Division For Planetary Sciences Issues Statement On Mars 2020 Program

Curiosity Maneuver Prepares for Drilling

STELLAR CHEMISTRY
Supersonic skydiver even faster than thought

Ahmadinejad says ready to be Iran's first spaceman

Iran's Bio-Capsule Comes Back from Space

A Hero For Humankind: Yuri Gagarin's Spaceflight

STELLAR CHEMISTRY
Reshuffle for Tiangong

China to launch 20 spacecrafts in 2013

Mr Xi in Space

China plans manned space launch in 2013: state media

STELLAR CHEMISTRY
NASA to Send Inflatable Pod to International Space Station

ISS to get inflatable module

ESA workhorse to power NASA's Orion spacecraft

Competition Hopes To Fine Tune ISS Solar Array Shadowing

STELLAR CHEMISTRY
Final checkout underway for the Starsem Soyuz launch with Globalstar spacecraft

Zenit Engine Worked Normally

NASA Launches Rocket from Wallops Flight Facility in Virginia

Intelsat 27 Launch Unsuccessful

STELLAR CHEMISTRY
Are Super-Earths Actually Mini-Neptunes?

Herschel Finds Past-Prime Star May Be Making Planets

Stars can be late parents

Researchers develop model for identifying habitable zones around star

STELLAR CHEMISTRY
South Korean Satellite Makes First Contact with Ground

Novel materials shake ship scum

Penn Research Shows Mechanism Behind Wear at the Atomic Scale

NTU research embraces laser and sparks cool affair




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