Headlines > News > NASA's Kepler Discovers Multiple Planets Orbiting a Pair of Stars

NASA's Kepler Discovers Multiple Planets Orbiting a Pair of Stars

Published by Klaus Schmidt on Wed Aug 29, 2012 12:37 pm via: NASA
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MOFFETT FIELD, Calif. — NASA’s Kepler mission has discovered multiple transiting planets orbiting two suns for the first time. The system, known as a circumbinary planetary system, is 4,900 light-years from Earth in the constellation Cygnus.

Coming less than a year after the announcement of the first circumbinary planet, Kepler-16b, this discovery proves that more than one planet can form and persist in the stressful realm of a binary star. The discovery demonstrates the diversity of planetary systems in our galaxy.

Sharing the Light of Two Suns: This artist's concept illustrates Kepler-47, the first transiting circumbinary system.  Credit: NASA/JPL-Caltech/T. Pyle

Sharing the Light of Two Suns: This artist's concept illustrates Kepler-47, the first transiting circumbinary system. Credit: NASA/JPL-Caltech/T. Pyle

Astronomers detected two planets in the Kepler-47 system, a pair of orbiting stars that eclipse each other every 7.5 days from our vantage point on Earth. One star is similar to the sun in size, but only 84 percent as bright. The second star is diminutive, measuring only one-third the size of the sun and less than 1 percent as bright.

“In contrast to a single planet orbiting a single star, the planet in a circumbinary system must transit a ‘moving target.’ As a consequence, time intervals between the transits and their durations can vary substantially, sometimes short, other times long,” said Jerome Orosz, associate professor of astronomy at San Diego State University and lead author of the paper. “The intervals were the telltale sign these planets are in circumbinary orbits.”

The inner planet, Kepler-47b, orbits the pair of stars in less than 50 days. While it cannot be directly viewed, it is thought to be a sweltering world, where the destruction of methane in its super-heated atmosphere might lead to a thick haze that could blanket the planet. At three times the radius of Earth, Kepler-47b is the smallest known transiting circumbinary planet.

The outer planet, Kepler-47c, orbits its host pair every 303 days, placing it in the so-called “habitable zone,” the region in a planetary system where liquid water might exist on the surface of a planet. While not a world hospitable for life, Kepler-47c is thought to be a gaseous giant slightly larger than Neptune, where an atmosphere of thick bright water-vapor clouds might exist.

“Unlike our sun, many stars are part of multiple-star systems where two or more stars orbit one another. The question always has been — do they have planets and planetary systems? This Kepler discovery proves that they do,” said William Borucki, Kepler mission principal investigator at NASA’s Ames Research Center in Moffett Field, Calif. “In our search for habitable planets, we have found more opportunities for life to exist.”

Orbiting in the Habitable Zone of Two Suns: This diagram compares our own solar system to Kepler-47, a double-star system containing two planets, one orbiting in the so-called "habitable zone."  Credit: NASA/JPL-Caltech/T. Pyle

Orbiting in the Habitable Zone of Two Suns: This diagram compares our own solar system to Kepler-47, a double-star system containing two planets, one orbiting in the so-called "habitable zone." Credit: NASA/JPL-Caltech/T. Pyle

To search for transiting planets, the research team used data from the Kepler space telescope, which measures dips in the brightness of more than 150,000 stars. Additional ground-based spectroscopic observations using telescopes at the McDonald Observatory at the University of Texas at Austin helped characterize the stellar properties. The findings are published in the journal Science.

“The presence of a full-fledged circumbinary planetary system orbiting Kepler-47 is an amazing discovery,” said Greg Laughlin, professor of Astrophysics and Planetary Science at the University of California in Santa Cruz. “These planets are very difficult to form using the currently accepted paradigm, and I believe that theorists, myself included, will be going back to the drawing board to try to improve our understanding of how planets are assembled in dusty circumbinary disks.”

The planets Kepler-47b and Kepler-47c: Kepler-47b has three times the radius of earth and orbits the pair of stars in less than 50 days while Kepler-47c is thought to be a gaseous giant, slightly larger than Neptune with an orbital period of 303 days.  Credit: NASA/JPL-Caltech/T. Pyle

The planets Kepler-47b and Kepler-47c: Kepler-47b has three times the radius of earth and orbits the pair of stars in less than 50 days while Kepler-47c is thought to be a gaseous giant, slightly larger than Neptune with an orbital period of 303 days. Credit: NASA/JPL-Caltech/T. Pyle

Ames manages Kepler’s ground system development, mission operations and science data analysis. NASA’s Jet Propulsion Laboratory in Pasadena, Calif., managed the Kepler mission development.

Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

The Space Telescope Science Institute in Baltimore archives, hosts and distributes Kepler science data. Kepler is NASA’s tenth Discovery Mission and funded by NASA’s Science Mission Directorate at the agency’s headquarters in Washington.

1 Comments
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This is insane. Not only could aliens be looking at two stars in their sky, they could be living on a moon orbiting a gas giant orbiting two stars. Add a ring and couple of other moons to the picture, and we have all the elements ever used in fiction to make night or day sky visually appealing and look alien. :) Now top that all off with the fact that that gas giant is orbiting in a zone where liquid water could exist on the surface of the moons that it probably has and let your imagination run wild. :)

So when are we going to get some very long base orbital interferometry happen to do detailed spectroscopy of the atmospheres of these planets and possible moons around them? :)

What would be the technological requirements of detecting life on Earth from 500-1000 light years away?

I mean for instance one possible way is to look at the reflected light and look for signs of organic chemistry. Could we detect chlorophyl from 1000 light years if we looked at Earth? And how could we do that? Or what about seasonal changes in leaf cover in the temperate regions.

What are the requirements of a telescope capable of gathering enough information to detect such subtle changes in the spectrum of light reflected by a planet?

Anybody has some info on this or should I justg google? :P
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