An automated telescope on a California mountaintop, the first fully robotic aid to astronomers hunting for distant worlds, has already found two new planetary systems, researchers say.
Operated by the University of California's Lick Observatory on Mt. Hamilton east of San Jose, the Automated Planet Finder began zeroing in on nearby stars in January in a search for Earth-size planets.
The self-operating telescope checks weather conditions every night and decided on candidate stars to observe. Moving from one star to another as the night progresses, it records data to aid the hunt for planets outside our solar system astronomers called "exoplanets."
In recent years large numbers of exoplanets have been identified by both telescopes based on Earth and NASA's Kepler space observatory.
While Kepler concentrated on stars at great distances and could only observe small areas of the sky, the APF telescope is concentrating on stars close to us and can scan all of the sky, researchers said.
"The planetary systems we're finding are our nearest neighbors. Those are the ones that will matter to future generations," says APF project leader Steve Vogt, professor of astronomy and astrophysics at UC Santa Cruz.
The first two planetary systems detected by the APF include one with four gas giant planets, similar to the four gas giant planets in our solar system although their orbits are much nearer their star, and another with a Neptune-mass planet in orbit around a red dwarf star.
While these are similar to a number of other systems already identified, the APF has the sensitivity to detect the ultimate goal, Vogt says -- an Earth-sized planet orbiting a nearby star in the habitable zone that could have liquid water on its surface.
The APF combines a 7.8-foot telescope and a spectrometer designed by Vogt specifically for planet hunting. The instrument makes repeated measurements of a star's spectrum to detect the tiny wobble in a star resulting from the gravitational pull of an orbiting planet.
While the telescope is relatively small compared to more famous instruments like the 33-foot Keck telescope in Hawaii, state-of-the-art optical technology gives it extremely high optical efficiency, says Vogt, who also designed the spectrometer for the Keck and other telescopes.
"We can do the same work we did at Keck, except now we have the APF every night instead of just a few nights per month at Keck," Vogt says. "What we're learning from all of this -- from Kepler and from our own work -- is that there's a huge number of planets out there, more planets than there are stars, and they're everywhere, including right next door to us."
