NASA finds star as cold as North Pole
May 3 FOX News
A brown dwarf as cold as the North Pole has been discovered lurking
remarkably close to our solar system, and it appears to be the coldest
of its kind yet found, scientists say.
Using NASA's Wide-field Infrared Survey Explorer (WISE) and Spitzer
Space Telescope, astronomers discovered the dim, "failed star" lurking
just 7.2 light-years away, making it the fourth closest system to our
sun."It's very exciting to discover a new neighbor of our solar system
that is so close," Kevin Luhman, an astronomer at Pennsylvania State
University's Center for Exoplanets and Habitable Worlds, said in a
statement. "And given its extreme temperature, it should tell us a lot
about the atmospheres of planets, which often have similarly cold
temperatures."
Brown dwarfs are sometimes called failed stars because they have many
of the elements of that make up stars, but they lack the huge mass
needed to kick off nuclear fusion in their core. As a result, these
objects don't radiate starlight and they sometimes resemble planets.
Some are even cool enough to have atmospheres much like gas giants.While
brown dwarfs are hidden in images taken in the visible spectrum,
infrared telescopes like WISE can pick up the meager glow of brown
dwarfs.Luhman and colleagues first spotted the object in WISE data. It
appeared to be moving quite fast, hinting that it was close by. The team
then investigated the object using Spitzer and the Gemini South
telescope on Cerro Pachon in Chile to measure its distance and
temperature.
ÓIt is remarkable that even after many decades of studying the sky,
we still do not have a complete inventory of the sun's nearest
neighbors," Michael Werner, the project scientist for Spitzer at NASA's
Jet Propulsion Laboratory in Pasadena, Calif., said in a statement.
Dubbed WISE J085510.83-071442.5, our newfound neighbor is now the
record-holder for the coldest brown dwarf, with a temperature between
minus 54 and 9 degrees Fahrenheit, Luhman and colleagues say. The
previous record holders were more tepid, chilling only to room
temperature.At 3 to 10 times the mass of Jupiter, the object also may be
one of the least massive brown dwarfs ever found, the astronomers say.
Because it is so small, the scientists say it's possible that the
body is actually a planet ejected from its star system, but brown dwarfs
are known to be quite common cosmic objects.The findings were described
April 21 in The Astrophysical Journal. Last year, Luhman used WISE data
to reveal a pair of warmer brown dwarfs with a possible exoplanet 6.5
light years away. At such a close distance, that system, dubbed WISE
J104915.57-531906, is the third nearest to the sun. The two closer
systems are Barnard's star, a red dwarf 6 light-years away that was
first seen in 1916, and Alpha Centauri, whose two main stars form a
binary pair about 4.4 light-years away.
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