Hubble glimpses oldest and rarest stars
Hubble views rare stars
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Friday, 18, Aug 2006 12:38
Astronomers have been offered a rare glimpse of some of the galaxy's oldest and dimmest stars through the Hubble space telescope.
Writing in this week's Science journal, the scientists outline how they have been able to gain a greater insight into two mysterious star types - slow burners less than one tenth the size of our sun and once giant stars that glow more than ten million years after their death.
Study co-author Jay Anderson, a research scientist at Rice University, said that the project to assess the stars even pushed the limits of what Hubble can do, as they can not be detected through single images and so need a large number of images to find them.
Hubble was focussed on the same patch of sky for more than 75 hours, collating more than 378 overlapping images of a globular cluster of stars that formed early in our galaxy's history.
"Globular clusters offer unique opportunities for astronomers to study a population of stars that are all the same age," Dr Anderson said. "All the stars we see in clusters are ancient, because they were created when the galaxy was forming. They're fossils from the galaxy's earliest days."
It is thought that the images and data gathered from them could help to verify and refine theories about the structure and evolution of low-mass stars. The brightness of the once giant stars could help scientists to narrow estimates of the lower limit of the age of the universe as it helps them to determine how long they have been cooling and therefore how old the cluster is.