U.S. astronomers have discovered a brown dwarf star that contradicts the perception of all stars being hot -- this one is, in fact, room temperature, they say.

Like normal stars, brown dwarfs form from collapsing gas clouds, but they don't become massive enough to sustain nuclear reactions, so they briefly shine red from the heat of formation then fade.

Still, before discovering this latest star, the coolest known brown dwarfs were determined to be hot enough to roast any astronauts who might approach too close, NewScientist.com reported Monday.

Pennsylvania State University astronomers used NASA's infrared Spitzer Space Telescope to detect the glow of this brown dwarf just 63 light years from Earth with a temperature of only 86 degrees Fahrenheit.

The object, orbiting a white dwarf star, has seven times the mass of Jupiter, a figure that would normally classify it as a planet.

Planets, however, form in discs of gas and dust around stars, researchers say, and this object -- dubbed WD 0806-661 B --lies too far from its star to be deemed a planet if it formed where it now is.

While hotter than Jupiter, which is at minus 236 degrees F., it is much cooler than the next coolest known brown dwarf star, measured at 212 degrees F.

This means that WD 0806-661 B will act as a "missing link" to reveal how temperature affects the atmosphere and features of objects that are roughly the size of Jupiter, the astronomers said.