Found: The Dimmest Bulbs in Space. "A pair of failed stars (brown dwarfs) takes the record of being the dimmest bulbs ever detected, astronomers find"
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In this image provided by NASA shows a new image from NASA's Spitzer Space Telescope showing a turbulent star-forming region, where rivers of gas and stellar winds are eroding thickets of dusty material. The picture provides some of the best examples yet of the ripples of gas, or bow shocks, that can form around stars in choppy cosmic waters. The cloud, called M17, or the Swan nebula, is located about 6,000 light-years away in the constellation Sagittarius. It is dominated by a central group of massive stars -- the most massive stars in the region. These central stars give off intense flows of expanding gas, which rush like rivers against dense piles of material, carving out the deep pocket at center of the picture. Winds from the region's other massive stars push back against these oncoming rivers, creating bow shocks like those that pile up in front of speeding boats. This picture was taken with Spitzer's infrared array camera and provided Monday Dec. 8, 2008.
(AP Photo/NASA/JPL)Found: The Dimmest Bulbs in Space
A pair of failed stars takes the record of being the dimmest bulbs ever detected, astronomers find.
Each of the substellar objects, called brown dwarfs, is one million times fainter than the sun in total light on the electromagnetic spectrum, and at least one billion times fainter in visible light alone.
A brown dwarf is a compact ball of gas floating freely in space that's too cool and lightweight to generate the thermonuclear fusion that powers real stars, but too warm and massive to be considered a planet.
"These brown dwarfs are the lowest-power stellar light bulbs in the sky that we know of," said lead researcher Adam Burgasser, a physicist at MIT.
The findings were published in the Astrophysical Journal Letters on Dec. 10.
Until now, astronomers thought this dim duo was a single, faint brown dwarf. Past research has shown the object is the fifth closest known brown dwarf to us, 17 light-years away toward the constellation Antlia. One light-year is the distance light will travel in a year, or about 6 trillion miles (10 trillion kilometers).
Here's how the team found the singlet was actually twins: They observed the object in infrared light using NASA's Spitzer Space Telescope. The data showed that what was still thought to be a single object had a warm atmospheric temperature of 560 to 680 degrees Fahrenheit (293 to 360 degrees Celsius). While this is hundreds of degrees hotter than Jupiter, it's still downright cold as far as stars go.
In fact, the brown dwarfs, called 2MASS J09393548-2448279, or 2M 0939 for short, are among the coldest brown dwarfs measured so far.
They also estimated the brightness, which they found to be twice what would be expected for a brown dwarf with its particular temperature. The solution: The object must have twice the surface area. So each body shines only half as bright, and each has a mass of 30 to 40 times that of Jupiter.
Burgasser said that studying these objects could help astronomers understand details of brown dwarf structure and evolution.
The work was funded in part by a NASA grant.
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