Twin stars observed in the Orion Nebula. At this distance the twin stars appear as a single point of light.
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Image Courtesy of NASA-JPL/HST and David James (Vanderbilt)
Newly Born Twin Stars are Far From Identical
News story originally written on June 18, 2008
Two stars, each with the same mass and in orbit around each other, are twins that one would expect to be identical. So astronomers were surprised when they discovered that twin stars in the Orion Nebula were not identical at all. In fact, these stars showed significant differences in brightness, surface temperature, and possibly even size.
It seems that one of the stars formed significantly earlier than its twin. Because astrophysicists have assumed that twin stars form at the same time, this new discovery adds an important new challenge for today's star formation theories and will force scientists to look back at their models to see if their models can produce twin stars that have formed at different times.
This new discovery may cause astronomers to readjust their estimates for thousands of young stars.
The newly formed twin stars are about 1 million years old. With a full life span of about 50 billion years, that makes them equivalent to one-day-old human babies.
"The easiest way to explain the observed differences is if one star was fully formed about 500,000 years before its twin. That would be equivalent to a human birth-order difference of about half a day," said Keivan Stassun, associate professor of astronomy at Vanderbilt University.
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