Hubble helps find smallest object in Kuiper Belt

Half-mile speck beyond Neptune located from 4.2 billion miles away

December 17, 2009|By Frank D. Roylance | Baltimore Sun reporter

A California scientist using the Hubble Space Telescope has discovered the smallest object ever seen in the Kuiper Belt - the vast region of icy objects beyond the orbit of Neptune.

The unnamed object is estimated to be 3,200 feet in diameter - just over a half-mile. Hubble detected it from 4.2 billion miles. The next-smallest known Kuiper Belt object is 30 miles in diameter.

CalTech astronomer Hilke Schlichting and her team found the tiny object by scouring 4 1/2 years of data from Hubble's Fine Guidance Sensor.

Computers searched the data from 50,000 Hubble guide stars and detected the object as it passed in front of one of them, dimming the starlight for three-tenths of a second. From the amount and duration of dimming, Schlichting's team estimated the object's size and distance.

"I was very thrilled to find this in the data," she said. The discovery was published in today's issue of the journal Nature. Hubble research is managed at the Space Telescope Science Institute in Baltimore.

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