Feb. 8 (Bloomberg) -- Astronomers have found the smallest known celestial body with planet-building material around it, providing a clue to how planets form and raising the question of whether life could emerge in such a system, NASA said.

A disc of dusty material surrounding a so-called ``brown dwarf,'' or ``failed star'' was found six months ago by astronomer Kevin Luhman and colleagues at the Gemini Observatory in Chile, using NASA's orbiting Spitzer Space Telescope, the U.S. National Aeronautics and Space Administration said in a statement e-mailed today.

The brown dwarf, called OTS 44, is about 15 times Jupiter's mass, half the size of the previous smallest known body to host a planet-forming disc, NASA said. The discovery ``will ultimately help astronomers better understand how and where planets, including rocky ones resembling our own, form,'' it said.

``In this case, we are seeing the ingredients for planets around a brown dwarf near the dividing line between planets and stars,'' said Giovanni Fazio, an astronomer at the Harvard Smithsonian Center for Astrophysics who co-wrote a paper on the finding with Luhman. ``This raises the tantalizing possibility of planet formation around objects that themselves have planetary masses.''

The disc of dust seen orbiting the brown dwarf is a precursor to planetary formation, and has the potential to form a gas giant planet, like Jupiter, and ``a few'' rocky earth-sized bodies, NASA said. Brown dwarfs resemble stars in that they are often found alone in space, and are similar to planets in that they lack the energy necessary to ignite.

Potential For Life?

``There may be a host of miniature solar systems out there, in which planets orbit brown dwarfs,'' Luhman said in the statement, adding that the discovery raises the question of whether habitable planets such as Earth could be found near a brown dwarf.

``If life did exist in this system, it would have to constantly adjust to the dwindling temperatures of a brown dwarf,'' the scientist said. ``For liquid water to be present, the planet would have to be much closer to the brown dwarf than Earth is to our sun''

OTS 44 is about 500 light-years away in the Chamaeleon constellation. The astronomers' findings were presented yesterday at the Aspen Center for Physics, in Aspen, Colorado, and the paper will be published on Feb. 10 in The Astrophysical Journal Letters.

To contact the reporter on this story: Alex Morales in London at amorales2@bloomberg.net.

Last Updated: February 8, 2005 09:36 EST