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New Method of Finding Planets Scores its First Discovery Detecting Alien Worlds
Monday, May 13, 2013 7:04
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New Method of Finding Planets Scores its First Discovery Detecting Alien Worlds
(Phys.org) —Detecting alien worlds presents a significant challenge since they are small, faint, and close to their stars.
The two most prolific techniques for finding exoplanets are radial velocity (looking for wobbling stars) and transits (looking for dimming stars).
A team at Tel Aviv University and the Harvard-Smithsonian Center for Astrophysics (CfA) has just discovered an exoplanet using a new method that relies on Einstein’s special theory of relativity.
“Einstein’s planet,” formally known as Kepler-76b, is a “hot Jupiter” that orbits its star every 1.5 days. Its diameter is about 25 percent larger than Jupiter and it weighs twice as much. This artist’s conception shows Kepler-76b orbiting its host star, which has been tidally distorted into a slight football shape (exaggerated here for effect). The planet was detected using the BEER algorithm, which looked for brightness changes in the star as the planet orbits due to relativistic BEaming, Ellipsoidal variations, and Reflected light from the planet. Credit: David A. Aguilar (CfA)
“We are looking for very subtle effects. We needed high quality measurements of stellar brightnesses, accurate to a few parts per million,” said team member David Latham of the CfA.
“This was only possible because of the exquisite data NASA is collecting with the Kepler spacecraft,” added lead author Simchon Faigler of Tel Aviv University, Israel.
Although Kepler was designed to find transiting planets, this planet was not identified using the transit method. Instead, it was discovered using a technique first proposed by Avi Loeb of the CfA and his colleague Scott Gaudi (now at Ohio State University) in 2003.
The new method looks for three small effects that occur simultaneously as a planet orbits the star. Einstein’s “beaming” effect causes the star to brighten as it moves toward us, tugged by the planet, and dim as it moves away.
The brightening results from photons “piling up” in energy, as well as light getting focused in the direction of the star’s motion due to relativistic effects.
“This is the first time that this aspect of Einstein’s theory of relativity has been used to discover a planet,” said co-author Tsevi Mazeh of Tel Aviv University.
“Einstein’s planet,” formally known as Kepler-76b, is a “hot Jupiter” that orbits its star every 1.5 days. Its diameter is about 25 percent larger than Jupiter and it weighs twice as much.
It orbits a type F star located about 2,000 light-years from Earth in the constellation Cygnus.
The planet is tidally locked to its star, always showing the same face to it, just as the Moon is tidally locked to Earth. As a result, Kepler-76b broils at a temperature of about 3,600 degrees Fahrenheit.
Journal reference: Astrophysical Journal
Provided by Harvard-Smithsonian Center for Astrophysics
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