Medical and Hospital News  
STELLAR CHEMISTRY
A nearby river of stars
by Staff Writers
Washington DC (SPX) Feb 18, 2019

Night sky centered on the south Galactic pole in a so-called stereographic projection. In this special projection, the Milky Way curves around the entire image in an arc. The stars in the stream are displayed in red and cover almost the entire southern Galactic hemisphere, thereby crossing many well-known constellations. Background image: Gaia DR2 skyma

Astronomy and Astrophysics publishes the work of researchers from the University of Vienna, who have found a river of stars, a stellar stream in astronomical parlance, covering most of the southern sky. The stream is relatively nearby and contains at least 4000 stars that have been moving together in space since they formed, about 1 billion years ago.

Due to its proximity to Earth, this stream is a perfect workbench on which to test the disruption of clusters, measure the gravitational field of the Milky Way, and learn about coeval extrasolar planet populations with upcoming planet-finding missions. For their search, the authors used data from the ESA Gaia satellite.

Our own host galaxy, the Milky Way, is home to star clusters of variable sizes and ages. We find many baby clusters within molecular clouds, fewer middle-age and old age clusters in the Galactic disk, and even fewer massive, old globular clusters in the halo.

These clusters, regardless of their origin and age, are all subject to tidal forces along their orbits in the Galaxy. Given enough time, the Milky Way gravitational forces relentlessly pull them apart, dispersing their stars into the collection of stars we know as the Milky Way.

"Most star clusters in the Galactic disk disperse rapidly after their birth as they do not contain enough stars to create a deep gravitational potential well, or in other words, they do not have enough glue to keep them together.

Even in the immediate solar neighborhood, there are, however, a few clusters with sufficient stellar mass to remain bound for several hundred million years. So, in principle, similar, large, stream-like remnants of clusters or associations should also be part of the Milky Way disk." says Stefan Meingast, lead author of the paper published in Astronomy and Astrophysics.

Thanks to the precision of the Gaia measurements, the authors could measure the 3D motion of stars in space. When carefully looking at the distribution of nearby stars moving together, one particular group of stars, as yet unknown and unstudied, immediately caught the eye of the researchers.

It was a group of stars that showed precisely the expected characteristics of a cluster of stars born together but being pulled apart by the gravitational field of the Milky Way.

"Identifying nearby disk streams is like looking for the proverbial needle in a haystack. Astronomers have been looking at, and through, this new stream for a long time, as it covers most of the night sky, but only now realize it is there, and it is huge, and shockingly close to the Sun" says Joao Alves, second author of the paper.

"Finding things close to home is very useful, it means they are not too faint nor too blurred for further detailed exploration, as astronomers dream."

Due to sensitivity limitations of the Gaia observations, their selection only contained about 200 sources. An extrapolation beyond these limits suggests the stream should have at least 4000 stars, thereby making the structure more massive than most know clusters in the immediate solar neighborhood.

The authors also determined the stream's age to be around one billion years. As such, it already has completed four full orbits around the Galaxy, enough time to develop the stream-like structure as a consequence of gravitational interaction with the Milky Way disk.

"As soon as we investigated this particular group of stars in more detail, we knew that we had found what we were looking for: A coeval, stream-like structure, stretching for hundreds of parsecs across a third of the entire sky." Says Verena Furnkranz, co-author and Masters student at the University of Vienna. "It was so thrilling to be part of a new discovery" she adds.

This newly discovered nearby system can be used as a valuable gravity probe to measure the mass of the Galaxy. With follow-up work, this stream can tell us how galaxies get their stars, test the gravitational field of the Milky Way, and, because of its proximity, become a wonderful target for planet-finding missions. The authors hope to unravel even more such structures in the future with the help of the rich Gaia database.

Research paper


Related Links
Astronomy and Astrophysics
Stellar Chemistry, The Universe And All Within It


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


STELLAR CHEMISTRY
Liberal sprinkling of salt discovered around a young star
Charlottesville VA (SPX) Feb 08, 2019
A team of astronomers and chemists using the Atacama Large Millimeter/submillimeter Array (ALMA) has detected the chemical fingerprints of sodium chloride (NaCl) and other similar salty compounds emanating from the dusty disk surrounding Orion Source I, a massive, young star in a dusty cloud behind the Orion Nebula. "It's amazing we're seeing these molecules at all," said Adam Ginsburg, a Jansky Fellow of the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, and lead author of a ... read more

Comment using your Disqus, Facebook, Google or Twitter login.



Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

STELLAR CHEMISTRY
Amid border wall debate, 'smart' tech raises questions too

How the US military could build Trump's border wall

Slashing roadkill numbers for small and medium-sized mammals

Robot lifts bits of melted fuel at Japan's Fukushima plant

STELLAR CHEMISTRY
Angry Norway says Russia jamming GPS signals again

Kite-blown Antarctic explorers make most southerly Galileo positioning fix

Magnetic north pole leaves Canada, on fast new path

NOAA releases early update for World Magnetic Model

STELLAR CHEMISTRY
Orangutans make complex economic decisions

Uncovering the evolution of the brain

Sequencing of human gut genome reveals nearly 2,000 unknown bacteria species

Western lowland gorillas enjoy peaceful, dynamic familial relations

STELLAR CHEMISTRY
Danish economist picked to be new UN environment chief

Runner recounts killing mountain lion in 'fight for survival'

Hong Kong seizes $1m of rhino horn in record airport haul

Acacia ants' vibrational sensors can differentiate between nibbles and wind

STELLAR CHEMISTRY
Study shows hope for fighting disease known as Ebola of frogs

China measles Study has implications for worldwide epidemic control

Mosquitoes that carry malaria may have been doing so 100 million years ago

Tourists at upmarket Chinese ski resort hit by novovirus

STELLAR CHEMISTRY
Chinese movies dodge censors to shine at Berlin filmfest

Male privilege: The rural Hong Kong men who have special rights

Former Mao Zedong secretary and party critic dies at 101

China warns its citizens in Turkey to 'be more vigilant'

STELLAR CHEMISTRY
STELLAR CHEMISTRY








The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - 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. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.