Coming less than a year
after the announcement of the first circumbinary planet, Kepler-16b, NASA's
Kepler mission has exposed multiple transiting planets orbiting two suns for
the first time. This system, Known as a circumbinary planetary system, is 4.900
light-years from Earth in the group Cygnus.
This exposure confirm that
more than one planet can form and persist in the stressful dominion of a binary
star and Demonstrates the diversity of planetary systems in our galaxy.
Astronomer’s detected
two planets in the Kepler-47 system; a pair of orbiting stars eclipses each
other that 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, between the time intervals
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 circumbinary these planets are in orbits."
The inner planet,
Kepler-47b, orbits the pair of stars in less than 50 days. While it cannot be
viewed directly, 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? Proves that this discovery Kepler They does," said William
Borucki Kepler mission's principal investigator at NASA Ames Research Center in
Moffett Field, Calif... "In our search for habitable planets, we have
found more Opportunities for life to exist."
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, me included, will be going back to the drawing board to try to
Improve Our Understanding of how planets are assembled in dusty circumbinary
disks."
Manages Ames Kepler's
ground system development, mission operations and science data analysis. NASA's
Jet Propulsion Laboratory in Pasadena, Calif., Managed the Kepler mission
development.
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.
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