KECK OBSERVATORY
This artist's rendering shows a disc of gas where planets may be forming around the star DGTau, 450 light years from Earth.
Telescopes see
solar system
being bornThe 2 Keck mirrors combine
their light with optics that
erase atmospheric twinkle
WAIMEA, Hawaii >> Light from the two giant Keck telescopes on Mauna Kea have been linked for the first time to study a young star 450 light years from Earth, the Keck Observatory announced.
The result was the detection of a disc of gas where planets may be forming, starting 18 million miles from the star DG Tau, said astronomer Rachel Akeson, who headed a team at the California Institute of Technology in Pasadena.
Linking the two Keck telescopes let the team observe with 10 times as much sensitivity as a single Keck telescope, said Keck spokeswoman Laura Kraft.
Light from the telescopes was linked previously for testing, but the infrared observation of DG Tau in the constellation Taurus was the first scientific study with the combined instruments.
Observations were made from October to February and the findings were recently accepted for publication in Astrophysical Journal.
Each of the Keck telescopes has a mirror 33 feet across. The linkage process, called interferometry, creates a single instrument like a telescope with a mirror 279 feet across.
While the technique yields a lot of data, it provided no real picture of DG Tau. To take that final step, an artist at the National Aeronautics and Space Administration created a painting of what astronomers think the data mean.
The painting shows a young star heated by gravitational compression to more than a million degrees at its center but is not yet creating hydrogen fusion.
Heat from the star has blown away gas and dust within 18 million miles and heated dust outside that zone, Akeson said. "We're trying to measure the size of the hot material in the dust disc around DG Tau, where planets may form," she said.
Brighter stars similar to DG Tau were observed in the past. Keck interferometry now allows faint ones to be studied.
Using other techniques, more than 100 planets have been found outside our solar system, all giants like Jupiter. NASA hopes the study of dust around stars will eventually reveal small, Earth-like planets, a Keck statement said.
The DG Tau study also used the adaptive optics capability of the Keck instruments, a technique that removes the twinkle created by the Earth's atmosphere in starlight, said optics engineer Peter Wizinowich.
Interferometry is like throwing a rock into a lake, then throwing another rock and watching how the two sets of ripples interact, Akeson said.
The DG Tau research is the first scientific application of interferometry and adaptive optics together, Wizinowich said.
