'Ghost' Cluster May Reveal the Origins of the Milky Way Galaxy
When our galaxy was born about 13,000 billion years ago, clusters containing millions of stars emerged. Over time, though, these have disappeared. Now, scientists have spotted a few ancient clusters hidden behind younger stars and are understanding the beginnings of our galaxy.
Globular clusters are spherical-shaped or globular stellar groupings which contain millions of stars. There are about 200 of them in the Milky Way, but few are as interesting as the E 3 cluster.
This particular cluster is located about 30,000 light-years away in the southern constellation of Chameleon.
"This globular cluster, and a few similar ones-such as Palomar 5 or Palomar 14-are 'ghosts' because they appear to be in the last stages of their existence, and we say 'from the past' because they are very old," said Carlos de la Fuente Marcos, one of the researchers, in a news release. "They were formed when our galaxy was virtually new-born, 13,000 billion years ago."
E 3 is hidden behind younger and brighter objects located between the cluster and Earth. However, information from this cluster has been possible to analyze with the help of the Very Large Telescope.
"Unlike typical globular clusters, which contain hundreds of thousands and in some cases millions of stars, the object studied only has a few tens of thousands of them," said De la Fuente Marcos. "Additionally, it doesn't have the typical circular symmetry, but a much distorted, almost ghostly, rhomboidal shape, contorted by the galactic gravitational waves."
Interestingly, E 3 is also chemically homogeneous. This means that it doesn't have several star populations in its interior. This, in particular, is characteristic of an object that was created in block, in one single episode, which is like what is supposed to have happened when the Milky Way was born.
The findings reveal a bit more about E 3 and possibly also the history of our galaxy. With that said, the researchers hope to obtain new data in 2016 to study it a bit further.
The findings are published in the journal Astronomy & Astrophysics.
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