Posted: Thu, Jun 17, 2010, 6:54 AM ET (1054 GMT)
Planetary astronomers have made the first observation of a Kuiper Belt object (KBO) occulting a star, providing information on its size and albedo. An MIT-led time, reporting in this week's issue of the journal Nature, reported on observations of a KBO designated 55636 as it passed in front of a bright star last October. Astronomers used the observations to determine the KBO's radius, 143 kilometers, and its albedo. They found the object is highly reflective, a surprising result since other objects in the outer solar system have darker surfaces as solar radiation darkens icy surfaces and as dust accumulates.
