Kuiper Belt world measured in star pass

                                  Pluto is the biggest Kuiper Belt object known so far 

Astronomers say they have observed, for the first time, a distant icy world orbiting beyond Neptune as it passed briefly in front of a bright star.

This "stellar occultation" occurs when a planetary body hides a star as it moves across the sky.
A US-led team of 18 astronomy groups used the occasion to study KBO 55636 from the Kuiper Belt on the outskirts of the Solar System.
They tell the journal Nature that the occultation lasted only 10 seconds.
But this was enough time to determine the object's size and albedo, or reflectivity, the team said.
The Kuiper Belt is a collection of space objects, remnants from the Solar System's formation.
These objects lie beyond the orbit of the Solar System's most remote planet, Neptune.
The Kuiper Belt is similar to the asteroid belt, but instead of being composed of mainly rock and metal, most of its bodies are frozen volatiles - methane, ammonia and water.