A snapshot of a young star just starting its planetary "family" provides the best evidence yet that planets like Earth may be forming elsewhere in the universe, NASA said yesterday.
The star, about 1,320 trillion miles from Earth in the constellation Centaurus, is surrounded by a vast disc of dust in which baby planets may already have formed.
"We have detected a disc with two independent teams and it appears to have a hole that's as large as our entire solar system," said Dr David Koerner of NASA's Jet Propulsion Laboratory in Pasadena, California. "From this we are inferring that a solar system like our own is being constructed right within it," he told a news conference.
Dr Michael Werner added: "This star allows us to probe planetary formation as it was around our own Sun about four billion years ago."
Known as HR 4796, the star is not the first candidate for possible Earth-like planetary satellites but it is one of the closest and also represents a crucial period in planetary evolution.
This star may be a youthful cousin of Beta Pictoris, which is also a good prospect for a solar system like our own. But Beta Pictoris, whose surrounding dust disc was discovered in 1983, is about 200 million years old, while HR 4796 is about 10 million, a prime planet-making age.
If this star is forming a planetary system of its own, it is probably much more far-flung than the one that contains Earth, the National Aeronautics and Space Administration said in a separate statement. The disc is about three times the size of Pluto's orbit around the Sun.
The planetary disc was sighted by astronomers in Chile, Hawaii, Pasadena and Pennsylvania.
Nature magazine today publishes related observations by astronomers from the Joint Astronomy Center (JAC) in Hawaii and at the University of California, Los Angeles (UCLA).