This artist's conception compares a hypothetical solar system centered
around a tiny "sun" (top) to a known solar system centered around a star,
called 55 Cancri, which is about the same size as our sun. NASA's Spitzer
Space Telescope, in combination with other ground-based and orbiting
telescopes, discovered the beginnings of such a miniature solar system
500 light-years away in the Chamaeleon constellation.
The tiny system consists of an unusually small "failed" star, or brown
dwarf called Cha 110913-773444, and a surrounding disk of gas and dust
that might one day form planets. At a mass of only eight times that of
Jupiter, the brown dwarf is actually smaller than several known extrasolar
planets. The largest planet in the 55 Cancri system is about four Jupiter
masses.
Astronomers speculate that the disk around Cha 110913-773444 might have
enough mass to make a small gas giant and a few Earth-sized rocky planets,
as depicted here around the little brown dwarf.