Planetary formation may occur more quickly than previously thought.

A team of researchers observed a young star surrounded by a circumstellar disk of dusty material using data from 1983, 2008, 2009 and 2010. Planets often arise from these disks. The star, which the team estimates to be 10 million years old, is 450 light-years from Earth in the constellation Centaurus.

The infrared emission patterns of the star's system, which can be used to measure how much dust the disk contains, were very similar in 1983 and 2008, but in 2009 the infrared emission had dropped precipitously, and in 2010 it was almost gone. The results were detailed in the July 5 issue of Nature. (Scientific American is part of Nature Publishing Group.) Researchers contributed from University of California Los Angeles, U.C. San Diego, California State Polytechnic University, University of Georgia and The Australian National University.

The artist's conception of the solar system, filled with dust (before) and empty (after), illustrates the dramatic change between researchers' observations in 2008 and 2010.

Astronomers had never before witnessed such a rapid disappearance of interstellar dust, and it challenges prior models of planetary formation. The research team has some hypotheses about the cause of the rapid change but has not come to any conclusions yet.

Evelyn Lamb