Seven Sisters Star Cluster Controversy Solved

Seven Sisters Star4Good news for fans of that stargazer’s favorite, the Pleiades. Such star clusters are closer than astronomers supposed, most particularly when it comes to the iconic one known to many sky-watchers as the Seven Sisters.  

Not only does a new study, published in Science magazine by a team led by Carl Melis of the University of California, San Diego, put to rest a heated cosmic controversy over the distance to the Pleiades, but it may recast how we peg stellar distances.

More than 1,000 star clusters, groupings of thousands of similarly aged stars, litter the galaxy. The suggestion that the Pleiades was 10 percent farther away from us than long calculated had clouded study of these clusters. The discrepancies in distance left researchers scratching their heads for years, challenging  their basic understanding of how stars form and evolve.

Now though, Melis and colleagues report that a global network of radio telescopes has triangulated the distance to the star cluster.  The newly attained distance to the famous wintertime star cluster, located in the constellation Taurus, has been pinned down to 443 light-years.

Made up of scores of hot blue stars all around 100 million years old, the Pleiades is considered one of the closest star clusters to Earth and is therefore considered a great “cosmic laboratory” for helping us understand how they form and evolve.  Our own sun is believed to have been born in just such a cluster some 4.6 billion years ago.

Up until the 1990s, the distance to the Pleiades was estimated at 430 light-years, but the European stellar mapping satellite Hipparcos, launched in 1989, had made measurements of only about 390 light-years.

source : http://newswatch.nationalgeographic.com/2014/08/28/distance-to-famous-star-cluster-remeasured/





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