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17 April 2014 12:48 pm ,
Vol. 344 ,
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Cold 'Star' No Hotter Than a Summer's Day
22 March 2011 12:55 pm
Stars are stars, and planets are planets, and never the twain shall meet, right? Not quite. Brown dwarfs—so-called failed stars that are too small to sustain the stable burning of hydrogen—fall somewhere in between stars and planets when it comes to mass and temperature. Now, researchers have found two brown dwarfs that are colder than any previously seen—so cold and so small that they are almost like giant planets. In a paper published 20 March in The Astrophysical Journal Letters, a team reports on a brown dwarf about 63 light-years away whose temperature is barely 300 kelvin. That's 200 K cooler than the previous record holder and about as warm as a bright summer day on Earth. In a second study, to be published in an upcoming issue of The Astrophysical Journal, researchers describe another very cold brown dwarf (shown here in an infrared telescope image), whose estimated temperature is about 370 Kelvin. The two objects could be the first examples of a proposed class of ultra-cool brown dwarfs known as the Y-class. And because they are almost as cold as "gas giant" planets—Jupiter is about 150 K—studying them could offer a better handle on what the atmospheres of alien worlds look like.
For more information about these discoveries, see the 18 March issue of Science.
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