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August
6, 2009: NASA's new exoplanet-hunting Kepler space
telescope has detected the atmosphere of a known giant gas
planet, demonstrating the telescope's extraordinary scientific
capabilities. The discovery will be published Friday in the
journal Science.
 "As
NASA's first exoplanets mission, Kepler has made a dramatic
entrance on the planet-hunting scene," said Jon Morse,
director of the Science Mission Directorate's Astrophysics
Division at NASA Headquarters in Washington. "Detecting
this planet's atmosphere in just the first 10 days of data
is only a taste of things to come. The planet hunt is on!"
Right:
An artist's concept of an exoplanet orbiting close to its
sun.
Image credit: NASA
Launched March 6, 2009, from Cape Canaveral Air Force Station
in Florida, Kepler will spend the next three-and-a-half years
searching for planets as small as Earth, including those that
orbit stars in a warm "Goldilocks zone" where there
could be water. It will do this by looking for periodic dips
in the brightness of stars, which occur when orbiting planets
transit, or cross in front of, the stars.
"When
the light curves from tens of thousands of stars were shown
to the Kepler science team, everyone was awed; no one had
ever seen such exquisitely detailed measurements of the light
variations of so many different types of stars," said
William Borucki, the principal science investigator and lead
author of the paper.
The observations were collected from a planet called HAT-P-7,
known to transit a star located about 1,000 light years from
Earth. The planet orbits the star in just 2.2 days and is
26 times closer than Earth is to the sun. Its orbit, combined
with a mass somewhat larger than the planet Jupiter, classifies
this planet as a "hot Jupiter." It is so close to
its star, the planet is as hot as the glowing red heating
element on a kitchen stove.
HAT-P-7 was known before Kepler turned its attention to the
planet. Kepler's measurements are so precise, however, they
show something new: a smooth rise and fall of the light caused
by the changing phases of the planet, similar to the phases
of our own Moon. Kepler could also see the planet's light
vanish completely when it passed behind its parent star. This
vanishing act is called an "occultation."
Above: A comparison of ground-based and space-based
light curves for hot exoplanet HAT P7b. Image credit: NASA.
[Larger
image]
The
new Kepler data can be used to study this hot Jupiter in unprecedented
detail. The depth of the occultation and the shape and amplitude
of the light curve show the planet has an atmosphere with
a day-side temperature of about 4,310 degrees Fahrenheit.
Little of this heat is carried to the cool night side. The
occultation time compared to the main transit time shows the
planet has a circular orbit. The discovery of light from this
planet confirms the predictions by researchers and theoretical
models that the emission would be detectable by Kepler.
The observed brightness variation is just one and a half times
what is expected for a transit caused by an Earth-sized planet.
Although this is already the highest precision ever obtained
for an observation of this star, Kepler will be even more
precise after analysis software being developed for the mission
is completed.
"This
early result shows the Kepler detection system is performing
right on the mark," said David Koch, deputy principal
investigator of NASA's Ames Research Center at Moffett Field,
Calif. "It bodes well for Kepler's prospects to be able
to detect Earth-size planets."
Stay
tuned to Science@NASA for more results from Kepler.
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Editor: Dr.
Tony Phillips | Credit: Science@NASA
| more
information |
| For
images, animations and more information about the Kepler
mission, visit: http://www.nasa.gov/kepler
or http://kepler.nasa.gov
Kepler is a NASA Discovery mission. Ames is responsible
for the ground system development, mission operations
and science data analysis. NASA's Jet Propulsion Laboratory
in Pasadena, Calif., manages the Kepler mission development.
Ball Aerospace and Technologies Corp. of Boulder, Colo.,
is responsible for developing the Kepler flight system
and supporting mission operations.
NASA's
Future: US
Space Exploration Policy |
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