Go Back   IceInSpace > General Astronomy > Astronomy and Amateur Science

Reply
 
Thread Tools Rate Thread
  #1  
Old 16-02-2019, 10:12 AM
gary
Registered User

gary is offline
 
Join Date: Apr 2005
Location: Mt. Kuring-Gai
Posts: 5,914
Cool 120° stream of ~4000 stars across Milky Way identified as likely disrupted cluster

Using data from the Gaia satellite, researchers have identified a stream of
some 4000 stars that have been moving together through the Milky Way
since they formed some 1 billion years ago.

It is believed that the stars once formed a cluster in the Galactic disk
which was gravitationally torn apart by the Milky Way, now leaving this
"smoking gun" of a river of stars.

Remarkably we have been looking at them and through them all this
time without realising their likely origin.

Quote:
Originally Posted by phys.org
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.
Quote:
Originally Posted by phys.org
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 & Astrophysics.

Thanks to the precision of the Gaia measurements, the authors could measure the 3-D 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 Joćo 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."
Story and map here (click on image to enlarge) :-
https://phys.org/news/2019-02-river-...ghborhood.html

Paper (free) "Extended stellar systems in the solar neighborhood" by Meingast et. al. :-
https://www.aanda.org/articles/aa/ab...a34950-18.html
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 04:09 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Advertisement
Bintel
Advertisement
Testar
Advertisement