For the first time, astronomers have detected a disk of debris orbiting a sun-like star paired with a planet _ a combination of features the looks more like our solar system than any yet found.

The orbiting disk in the constellation Canceris is made up of dust, comets and other cosmic leftovers, and it extends for billions of miles beyond the star known as 55 Cancri.

Astronomers at the University of Arizona who discovered the disk said it is very similar in size and composition to the Kuiper Belt in our solar system. The Kuiper Belt begins beyond the orbit of Pluto about 5 billion miles from the Sun and extends into deep space.

``And, for all we know, there could be other similarities in this system yet to be discovered,'' said David Trilling, who along with planetary scientist Robert Brown report on the disk in today's issue of the journal Nature.

The star, about the same size and age as the sun, is about 40 light years away. Two years ago, scientists at San Francisco State University detected a gravity-induced wobble in the star's motion.

They calculated that the wobble was the result of a planet that probably has 1.9 times the mass of Jupiter. The planet is 50 times closer to its star than Jupiter is to the sun, making direct observation impossible.

In observations last February, the Arizona team attached a special instrument to a telescope atop Mauna Kea in Hawaii that blocked intense starlight coming from 55 Cancri. It allowed them to examine the infrared radiation reflected by the dust disk without interference from the star.

In recent years at least a dozen planets have been found in orbit of distant stars. All are the size of Jupiter or larger, and none is ``Earth-like.'' But their existence strongly suggests the existence of smaller planets potentially more friendly to life.

The National Aeronautics and Space Administration is now considering 30 proposals to search specifically for Earth-like planets. Trilling said 55 Cancri might be the most promising.