MessageToEagle.com

Astronomers Measured The Change In Position Of More Than 30,000 Stars
In Globular Cluster 47 Tucanae

19 July, 2013

Share this story:
Follow us:

MessageToEagle.com - Scientists of the University of British Columbia in Vancouver determined the motions of the stars in the globular cluster 47 Tucanae, which is located about 16,700 light-years away in the southern constellation Tucana.

The analysis enabled researchers, for the first time, to link the movement of stars in the clusters with the stars' ages. The two populations in 47 Tucanae differ in age by less than 100 million years.

"When analyzing the motions of stars, the longer the time baseline for observations, the more accurately we can measure their motion," said Harvey Richer, who led the research team. "These data are so good, we can actually see the individual motions of the stars in the cluster. The data offer detailed evidence to help us understand how various stellar populations formed in such clusters."



Click on image to enlarge

The ancient globular cluster 47 Tucanae, a dense swarm of up to a million stars.

The image at left shows the entire cluster, which measures about 120 light-years across. Located in the southern constellation Tucana, the cluster is about 16,700 light-years away. The image is part of the Sloan Digital Sky Survey and was taken by the UK Schmidt Telescope at Siding Spring Observatory in New South Wales, Australia. The white rectangular box outlines the view taken by NASA's Hubble Space Telescope. That image, shown at right, captures close-up views of thousands of cluster stars. The large, bright stars in the image are red giants. These stars have puffed up to several times their normal size because they have exhausted their nuclear fuel and are near the end of their lives. The image was taken by Hubble's Advanced Camera for Surveys. Credit: NASA, ESA, Digitized Sky Survey (DSS; STScI/AURA/UKSTU/AAO), H. Richer and J. Heyl (University of British Columbia), and J. Anderson and J. Kalirai (STScI)


47 Tucanae is 10.5 billion years old and one of the brightest of our galaxy's more than 150 globular clusters. The cluster measures about 120 light-years wide.

This Hubble analysis supports previous studies of stars with varying chemical compositions and adds the stars' orbital motion to the analysis.

Richer and his team used Hubble's Advanced Camera for Surveys to observe the cluster in 2010. They combined those observations with 754 archival images to measure the change in position of more than 30,000 stars.

Using these data, they could discern how fast the stars move. The team also measured the stars' brightness and temperatures.

This stellar archaeology identified the two distinct populations of stars.

The first population consists of redder stars, which are older, less chemically enriched, and orbiting in random circles. The second population consists of bluer stars, which are younger, more chemically enhanced, and moving in more elliptical orbits.

The lack of heavier elements in the redder stars reflects the initial composition of the gas that formed the cluster. After the most massive of these stars completed their stellar evolution, they expelled gas enriched with heavier elements back into the cluster.

This gas collided with other gas and formed a second, more chemically enriched generation of stars that was concentrated toward the cluster center. Over time these stars moved slowly outward into more elliptical orbits.

In 2007, Hubble researchers found three generations of stars in the massive globular cluster NGC 2808. But Richer's team is the first to link stellar dynamics to separate populations.

The team's results are published in the July 1 issue of the Astrophysical Journal Letters.


MessageToEagle.com

See also:
Fermi Detects Unknown Objects Producing Gamma Rays

Follow MessageToEagle.com for the latest news on Facebook and Twitter !

Don't Miss Our Stories! Get Our Daily Email Newsletter

Enter your email address:


Once you have confirmed your email address, you will be subscribed to the newsletter.

Recommend this article:

Teleportation Experiments Continue - Record-Breaking Distance of 143 Kilometers Achieved!

Violent Behavior Of Our Sun - Massive 500,000 Mile Long Filament Observed

First Massive Galaxies Lit Up The Early Universe

Intense Blue Lightning On Saturn Visible From Space In Broad Daylight!

Subscribe To Our Space, Astronomy, Astrophysics, Earth and Xenology News!

Grab the latest RSS feeds right to your reader, desktop or mobile phone.


comments powered by Disqus

Subscribe to RSS headline updates from:
Powered by FeedBurner

Go to - MAIN PAGE

Copyright © MessageToEagle.com All rights reserved.
Go to - MAIN PAGE


Get our top stories
Follow MessageToEagle.com

 Subscribe in a reader

Join Us On Facebook!

Other Popular Articles

Universe:


Juno Spacecraft's Critical Mission - To Uncover The Secrets Hidden Beneath Jupiter's Mysterious Clouds

What’s Going On Out There? - NASA's RBSP Spacecraft Will Meet ‘Killer Electrons’ And Other Dangerous Phenomena

New Photos Of Saturn And Its Moon Titan - See A Striking Change Of Colors!

Beautiful and Mysterious Superbubble In The Large Magellanic Cloud Observed By Chandra

WISE Discovers Millions Of Black Holes And 1,000 Extreme Galaxies Called Hot DOGS

Dawn Spacecraft Is Heading Towards Dwarf Planet Ceres To Investigate The Formation Of Our Solar System

Lunar Paradox Problem: Moon Origin In Focus Again!

There Is Sugar In That Star! Life Building Blocks Discovered Around A Sun-Like Star

First Planetary System Orbiting Two Suns Found By Kepler

Astronomers Test Einstein In A New Regime Using Pair of Burnt-Out Stars

The Universe Will Vanish In 100 Billion Years - Says Nobel Prize Winner Brian P. Schmidt

Our Creator Is A Cosmic Computer Programmer - Says JPL Scientist

Mysterious, Huge 'Pigtail' Molecular Cloud Discovered In The Galactic Center

Astronomers See The Infant Universe's Oldest Galaxies Yet!

Star With The Secret Of Eternal Youth

Physicists Challenge Validity Of Big Bang Theory

Space-Time Crystal Computer That Can Outlive Even The Universe Itself!

Dawn Spacecraft Is Heading Towards Dwarf Planet Ceres To Investigate The Formation Of Our Solar System

New Photos Of Saturn And Its Moon Titan - See A Striking Change Of Colors!

What’s Going On Out There? - NASA's RBSP Spacecraft Will Meet ‘Killer Electrons’ And Other Dangerous Phenomena

Mysterious X-Rays From Jupiter Near The Poles

W3Counter