Astronomers have captured the first direct image of a planetbeing born.
Adam Kraus, of the University of Hawaii's Institute forAstronomy, said the planet is being formed out of dust and gas circling a2-milion-year-old star about 450 light years from Earth.
The planet itself, based on scientific models of how planetsform, is estimated to have started taking shape about 50,000 to 100,000 yearsago.
Called LkCa 15 b, it's the youngest planet ever observed.The previous record holder was about five times older.
Kraus and his colleague, Michael Ireland from MacquarieUniversity and the Australian Astronomical Observatory, used Keck telescopes onMauna Kea to find the planet.
"We're catching this object at the perfect time. We seethis young star, it has a disc around it that planets are probably forming outof and we see something right in the middle of a gap in the disc," Kraussaid in a telephone interview.
Kraus presented the discovery Wednesday at NASA's GoddardSpace Flight Center in Maryland. Kraus and Ireland's research paper on thediscovery is due to appear in The Astrophysical Journal.
Observing planets while they're forming can help scientistsanswer questions like whether planets form early in the life of a star orlater, and whether they form relatively close to stars or farther away.
Planets can change orbits after forming, so it's difficultto answer such questions by studying older planets.
"These very basic questions of when and where are bestanswered when you can actually see the planet forming, as the process ishappening right now," Kraus said.
Other planets may also be forming around the same star.Kraus said he'll continue to observe the star and hopefully will see otherplanets if there are in fact more.
Scientists hadn't been able to see such young planets beforebecause the bright light of the stars they're orbiting outshines them.
Kraus and Ireland used two techniques to overcome thisobstacle.
One method, which is also used by other astronomers, was tochange the shape of their mirror to remove light distortions created by theEarth's atmosphere.
The other, unique method they used was to put masks overmost of the telescope mirror. The combination of these two techniques allowedthe astronomers to obtain high-resolution images that let them see the faintplanet next to the bright star.
The astronomers found the planet while surveying 150 youngdusty stars. This led to a more concentrated study of a dozen stars.
The star LkCa 15 — the planet is named after its star — wasthe team's second target. They immediately knew they were seeing something new,so they gathered more data on the star a year later.