Astronomers have captured what they call the strongest evidence yet of new planets forming around a nearby star.
Researchers have studied a few other stars where planets might be seen coalescing, but two independent scientific teams Tuesday said this one is the first where they could see what appears to be a planet-forming disc of gas and dust so clearly through the glare of its star. The star is located in the southern constellation Centaurus.
A third international team Tuesday released the first pictures of huge discs that may be forming planets around two other stars. Astronomers said the findings announced Tuesday should be only the beginning of a flurry of such discoveries made possible by new technologies.
The planet-forming disc in Centaurus surrounds the star HR 4796, roughly 220 light years from Earth. The star as observed is only about 10 million years old, astronomers said, and its disc of planet-forming
debris - though much larger in diameter - probably resembles our own solar system when it was in a similar phase perhaps 4.5 billion years ago.
The discovery appears to fill a blank in scientists' understanding of how worlds form in the debris that swirls around a newborn star, researchers said. Some also said it strengthens the case that there are other planets like Earth where life has arisen.
Astronomers have struggled to obtain unambiguous evidence for the existence of other planetary systems, even though in theory they are commonplace. In 1995, planet searchers found their first planet around another star and since then have confirmed eight. But the characteristics of these bodies and their settings are so unexpected and diverse that they have stirred up new mysteries.
The discovery, announced Tuesday at NASA headquarters and submitted for publication in the Astrophysical Journal Letters, represents a "missing link" in such studies, according to David Koerner of NASA's
Jet Propulsion Laboratory in Pasadena, Calif., a member of the team that used the new 10-meter Keck II telescope atop the extinct Mauna Kea volcano in Hawaii.
"In a sense, we've already peeked into the stellar family album and seen baby pictures and middle-aged photos. With HR 4796, we're seeing a picture of a young adult star starting its own family of planets."
The finding suggests that the formation of planets is common, he said, and "perhaps there are lots of places for life to exist."
"What's most exciting is that we are looking at a disc just at the time it is forming planets, or has recently done so," said Ray Jayawardhana of the Harvard Smithsonian Center for Astrophysics in Cambridge, Mass., who found the disc while working on his doctoral thesis.
He and Charles Telesco of the University of Florida led the second team, which used the National Science Foundation's 4-meter Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile to confirm
the HR 4796 disc about the same time in mid-March.
Planets form as natural byproducts of star formation, in theory, coagulating inside flattened clouds of gas and dust that rotate around a newborn star.