This artist's concept shows a brown dwarf surrounded by a swirling disc of planet-building dust. NASA's Spitzer Space Telescope spotted such a disc around a surprisingly low-mass brown dwarf, or "failed star." The brown dwarf, called OTS 44, is only 15 times the size of Jupiter, making it the smallest brown dwarf known to host a planet-forming, or protoplanetary disc. Astronomers believe that this unusual system will eventually spawn planets. If so, they speculate that OTS 44's disc has enough mass to make one small gas giant and a few Earth-sized rocky planets. OTS 44 is about 2 million years old. At this relatively young age, brown dwarfs are warm and appear reddish in color. With age, they grow cooler and darker. Credit: NASA/JPL-Caltech
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This artist's conception shows the relative size of a hypothetical brown dwarf-planetary system (below) compared to our own solar system. A brown dwarf is a cool or "failed" star, which lacks the mass to ignite and shine like our Sun. NASA's Spitzer Space Telescope set its infrared eyes on an extraordinarily low-mass brown dwarf called OTS 44 and found a swirling disc of planet-building dust. At only 15 times the mass of Jupiter, OTS 44 is the smallest known brown dwarf to host a planet-forming, or protoplanetary, disc. Astronomers believe that this unusual system will eventually spawn planets. If so, they speculate that OTS 44's disc has enough mass to make one small gas giant and a few Earth-sized rocky planets. Examples of these possible planets are depicted at the bottom of this picture, circling a low-mass brown dwarf. Above, the bodies of our own solar system have been drawn to the same scale. In each system, the terrestrial planets have been enlarged and the distances between the planets and their parent bodies have been scaled down for easier viewing. Credit: NASA/JPL-Caltech
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This graph of data from NASA's Spitzer Space Telescope shows that an extraordinarily low-mass brown dwarf, or "failed star," is circled by a disc of planet-building dust. The brown dwarf, called OTS 44, is only 15 times the mass of Jupiter, making it the smallest known brown dwarf to host a planet-forming disc. Spitzer was able to see this unusual disc by measuring its infrared brightness. Whereas a brown dwarf without a disc (red dashed line) radiates infrared light at shorter wavelengths, a brown dwarf with a disc (orange line) gives off excess infrared light at longer wavelengths. This surplus light comes from the disc itself and is represented here as a yellow dotted line. Actual data points from observations of OTS 44 are indicated with orange dots. Credit: NASA/JPL-Caltech/Harvard-Smithsonian CfA
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