Scientists discover large asteroid between Neptune, Pluto

If confirmed, the new asteroid would be second in size only to asteroid Ceres. Ceres is shown here in a NASA image

NEW HAVEN, Connecticut (CNN) -- Astronomers have discovered a new object orbiting the sun that is smaller than a planet but larger than most known asteroids.

Officially named 2000 EB173, the object is a ball of rock and ice measuring 373 miles (597 km) in diameter -- about one-fourth the size of the planet Pluto.

The object is classified as a minor planet, like thousands of other asteroids and comets in our solar system. It is second in size only to asteroid Ceres, which is 580 miles (940 km) in diameter and orbits between Mars and Jupiter.

Astronomers officially recognize nine major planets. EB173 is too small to fit that category.

Located 3.6 billion miles (5.8 billion km) from Earth, EB173 is part of the Kuiper Belt, a ring of icy debris orbiting the sun, located out beyond Neptune.

Astronomers believe the Kuiper Belt is filled with hundreds of thousands of small, icy objects. The first of these Kuiper Belt objects was discovered in 1992; since then more than 150 have been found. Many of them are upwards of 60 miles (96 km) in diameter. Several, including EB173, are much larger.

Pluto was discovered by Clyde Tombaugh in 1930. Many astronomers believe it would be classified as a minor planet in the Kuiper Belt if it were found today.

Astronomers are interested in studying the Kuiper Belt because they want to know more about how the Earth and other major planets formed. They think the icy bodies within the Kuiper Belt are well preserved remnants of the early solar system, which formed about 4.5 billion years ago.

Astronomers also think the Kuiper Belt is the source of so-called short period comets, like Halley's Comet, that periodically pass by Earth in orbit around the sun.

A team of astronomers led by Gustavo Bruzual of Venezuela's CIDA astronomy center and Charles Baltay of Yale University made the EB173 discovery. They intend to report their find in the publication Astronomical Journal Letters.

CNN's Kate Tobin contributed to this report.

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CIDA
The Astronomical Journal
Yale University

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