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Starry afterthought
Steve Kawaler and the Whole Earth Telescope contribute to major planetary discovery.
- It was nothing more than an afterthought.
There just happened to be extra observing time during a three-week run of the Whole Earth Telescope, a worldwide network of cooperating observatories that allow astronomers to take uninterrupted measurements of variable stars that change in brightness.
Steve Kawaler, professor of physics and astronomy, was responsible for organizing that observing run. He didn't give much thought to the third-priority target. After all, one of his own graduate students had gotten similar results on a similar star previously. Those findings didn't pan out after the initial excitement generated by the data.
So when WET made their observations during the 2003 run, they concentrated their efforts on their primary target - a supernova progenitor.
Now four years later, Kawaler can't tell you if anything came from the data collected for the primary target. As for the afterthought - well the data that Kawaler helped obtain may well turn out to be one of the most significant astronomical discoveries in recent years.
Kawaler is part of an international team of astronomers that announced recently in Nature of the first discovery of a planet orbiting a star near the end of its life. The star, in the constellation of Pegasus, represents the state of our own sun 4-5 billion years into the future. The announcement culminates seven years of research on the planet with the tongue-rolling name of "V 391 Pegasi b."
The discovery is important because it could provide a look into the future of what will happen to the Earth when the sun exhausts its hydrogen fuel, expands enormously as a red giant and expels its outer layers in an explosive helium flash.
Never before has a planet been observed that has survived such an evolution of a red giant.
"The exciting thing about finding a planet around this star is that it indicates that planetary systems can survive the giant phase and the helium flash of their parent star," Kawaler says. "This may indicate that the Earth could survive a similar expansion of the sun."
While "V 391 Pegasi b" is the first planet to be observed surviving a red giant expansion, there are differences between that planet and the Earth. The recently discovered planet is larger than Jupiter and Kawaler warns a smaller planet like Earth could still be vulnerable.
The international research team was led by Roberto Silvotti from the INAF-Osservatorio Astronomico di Capodimonte in Naples, Italy and a long-time collaborator of Kawaler's.
In addition to the role WET played in obtaining data, Kawaler advanced the project by doing theoretical calculations to make sure irregularities of the star's orbital motion were caused by the orbiting planet and not processes within the star itself.
"I am delighted to have been able to contribute to an extremely exciting discovery," Kawaler said.
The discovery has also got Kawaler dreaming again.
"This has made me think about why I and others got interested in astronomy and space as kids in the first place," he said, "you want to find aliens and this has me thinking again about life on other worlds around other stars."
Steve Kawaler (left) was joined in the study by former ISU students Mike Reed, Missouri State University, and Reed Riddle, Thirty Meter Telescope team.
Around LAS
October 1-14, 2007
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