Subscribe to our free daily newsletters
. 24/7 Space News .

Subscribe to our free daily newsletters

Astronomer detects new source of intense gamma-radiation in the sky
by Staff Writers
Moscow, Russia (SPX) Feb 18, 2016

This is an artist's impression of the clash of powerful stellar winds. Image courtesy NASA/C. Reed. For a larger version of this image please go here.

Analyzing the data collected by the Fermi Gamma-ray Space Telescope Maxim Pshirkov (The Sternberg Astronomical Institute, MSU) discovered a new source that confirmed the fact that binary systems with strong colliding stellar winds comprise a separate new population of high-energy gamma-ray sources.

Massive binary star systems with highly luminous and hot Wolf-Rayet stars and massive (tens solar masses) OB companion generate strong stellar winds. Its percussion may lead to producing a fierce photon flux with an energetic potential of more than a hundred mega electronvolt (MEV), when a distance separating stars is relatively short. That phenomenon was considered as a possible source of gamma-radiation for a long while.

Strong stellar winds are generated in the binary systems consisting of highly luminous and hot Wolf-Rayet stars and massive ( several tens solar masses) OB companions. Wind collision may produce strong photon emission with photon energies exceeding hundred mega electronvolts (MeV). This phenomenon was considered as a possible source of gamma-radiation for a long while.

Though such radiation was detected only once, with the famous Eta Carinae, which was observed for more than four centuries (particularly intensively - after 1834, when one of its stars underwebt an explosion and for some time was the most luminous star in the sky) ). Eta Carinae is comparatively close to Earth - around 7,5 - 8 thousand light years.

The stars in this system weight 120 and (30-80) solar masses respectively, and shine brighter than millions of suns. If they were 10 parsec (30 light years) away from the Earth, they would be just as luminous as the Moon, while the Sun would be invisible on such distance. Naturally, Eta Carinae was the first candidate to consider and seven years ago high-energy radiation from this system was finally detected.

However, one example was not enough to confirm the model of binary stars emitting high-energy radiation, and the search for similar sources was continued, which turned out to be a tricky task.

"Recent calculations proved such star types as Eta Carinae to be incredibly rare - probably, one per a galaxy like we inhabit, or less,' said Maxim Pshirkov, my colleagues' research resulted in no certain findings. In 2013 an American-Austrian research team composed a list of seven stellar systems containing Wolf-Rayet stars, where a radiation could most probably appear.

This research was based on two years of observations and lacked data, so it was only possible to set an upper limit on the HE radiation. I decided toutilize larger set of data seven years of Fermi-LAT observations. As the result - it was discovered that Gamma Velorum is the source of gamma-radiation at 6.s. confidence level"

This system contains two stars with masses of 30 and 10 solar masses. Their orbital parameters are well-studied and they are separated by about the same distance as Earth and Sun. The luminosity of this binary system is about 200 thousand times higher than of the Sun and strong stellar winds have very high mass loss rate: hundred-thousandth and two ten-millionth of the solar mass every year.

Though these figures seem to be small, actually this amount is huge, particularly comparing to the solar wind which only amounts to 10-14 solar mass per annum As the stellar winds in the Gamma Velorum system collide on a speed exceeding 1000 kilometers per second, particles are accelerated in the shock. Though an exact mechanism of this acceleration is still unknown, it definitely leads to a high energy photon radiation that turned out to be detected by Fermi LAT.

An attentive reader who followed the process of searching for Higgs boson in the Large Hadron Collider has probably faced the standard deviation that Pshirkov mentions and remembered that in physics a hypothesis is proved on a statistical accuracy higher than 5s.

That means it is confirmed with a probability higher than 99,999%. In other words Pshirkov's discovery with its six standard deviations is definitely reliable, though it's still not far away from the threshold. According to the article, it was partly a pure luck that helped the researcher.

"Searching for similar sources in the very galactic plane is much more complicated, since it is a powerful gamma-ray source itself, and detecting small photon excess coming from colliding stellar winds becomes much more difficult with this background," says the scientist.

"But the Gamma Velorum system lies above the plane surface and it is comparatively close to us. The discovery would not probably happen, if it was further away or closer to the plane."

Pshirkov's article was published in the latest issue of 'Monthly Notices of the Royal Astronomical Society Letters'

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once

credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly

paypal only


Related Links
Lomonosov Moscow State University
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 DiggDigg RedditReddit GoogleGoogle

Previous Report
Galactic center's gamma rays unlikely to originate from dark matter, evidence shows
Princeton NJ (SPX) Feb 04, 2016
Bursts of gamma rays from the center of our galaxy are not likely to be signals of dark matter but rather other astrophysical phenomena such as fast-rotating stars called millisecond pulsars, according to two new studies, one from a team based at Princeton University and the Massachusetts Institute of Technology and another based in the Netherlands. Previous studies suggested that gamma ra ... read more

NASA chooses ASU to design and operate special satellite

Aldrin recounts successes and challenges of historic space journey

Chinese scientists invent leak detection system for moon exploration

Edgar Mitchell, astronaut who walked on Moon, dead at 85

Somewhere between Earth and Mars Science Fiction Became Science Fact

Becoming a Martian

Site of Martian lakes linked to ancient habitable environment

Opportunity climbing steeper slopes to reach science targets

Flowering Zinnias set stage for deep-space food crop research

Practical Advice for Aspiring Space Explorers

Visions of the future unleashed at TED

Are private launches changing the rocket equation?

China Conducts Final Tests on Most Powerful Homegrown Rocket

Last Launch for Long March 2F/G

China aims for the Moon with new rockets

China shoots for first landing on far side of the moon

Black Mold Found in Cargo Prepared for ISS, Resupply Mission Delayed

Putting the Public in the Shoes of Space Station Science

Russians spacewalk to retrieve biological samples

Russia to Deliver Three Advanced Spacesuits to ISS in 2016

ULA Launches NROL-45 Payload for the National Reconnaissance Office

SES-9 Launch Targeting Late February

Spaceflight Awarded First GSA Schedule Contract for Satellite Launch Services

SpaceX to carry military payloads as US phases out Russian rocket engines

Volcanoes Light Up Atmospheres of Small Exoplanets

Planet formation around binary star

First detection of super-earth atmosphere

Proto-planet has 2 masters

Russian Scientists Against Using Nuclear Weapons to Clear Space Debris

Flow phenomena on solid surfaces

Honeywell developing virtual reality technologies for military

Body temperature triggers newly developed polymer to change shape

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

The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news 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. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. 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