If the planet passes in front of a relatively small star, the planet would block a lot of the star, so the planet would be easier to see. Having a low-mass star orbited by a higher-mass planet has advantages for detection. Thus, red stars would be "pulled around" much more easily by the mass of its orbiting planet. These stars, Lloyd said, are interesting because they have less mass than the already-discovered sunlike stars with exoplanets. TEDI will allow scientists to detect planets that orbit red stars, which cannot be measured with existing Doppler technology.
The project is funded by the National Science Foundation. Built at Cornell, the spectrometer is attached now to the Mount Palomar 200-Inch Hale Telescope operated by the California Institute of Technology. One of Lloyd's major projects focuses on an advanced form of the indirect measurement of exoplanets using an instrument called the Triple Spec Exoplanet Discovery Instrument (TEDI). Nearly all the known exoplanets, including CoRoT-7b, have been detected indirectly with a technique called precision Doppler spectroscopy, in which scientists infer the existence of a planet by observing the motion of the parent star through the Doppler effect on the star's light. But if a planet like CoRoT-7b were to be found orbiting a less massive, less luminous star - the kind that interests Lloyd - life on it would certainly be possible, he said. Not exactly a habitable environment, at least by Earth's standards. It orbits so closely to its star that its surface is a molten lava lake of 3,600 degrees Fahrenheit, and molten rock and lava rain from the sky. "This is a rocky planet, but it's nothing like the Earth," Lloyd explained. Calling this planet "Earthlike," however, would be a stretch, Lloyd said. But in recent weeks, a French-led team of scientists announced the discovery of the first confirmed rocky exoplanet, named CoRoT-7b. Up until recently, none of the known exoplanets were terrestrial - most are gas giants, like Jupiter and Saturn. "And that has a profound implication for how much life there might be out there in the universe."Īn experimental astrophysicist who has spent time in Chicago, California and at the South Pole, Lloyd develops instruments to search for new kinds of planets - ones with a hard surface, like ours, called terrestrial planets, and ones that exist in the so-called habitable zone, the distance from a star in which life could be possible. "We don't know whether our solar system is an incredibly rare configuration, or an incredibly common configuration," said Lloyd, who joined the Cornell faculty in 2004.
So far, about 370 exoplanets have been discovered, and more might lead to hints about the origins of our solar system. The Cornell assistant professor of astronomy works on instrumentation that searches the night skies for planets outside our solar system, called extrasolar planets or exoplanets. Somewhere in the galaxy, a rocky, blue-green planet like Earth, teeming with oxygen, water and life, might be orbiting its own sun.
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