NASA'S Kepler Mission Spies Changing Phases in a Distant World

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WASHINGTON -- 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.

The find is based on a relatively short 10 days of test data collected
before the official start of science operations. Kepler was launched
March 6, 2009, from Cape Canaveral Air Force Station in Florida. The
observation demonstrates the extremely high precision of the
measurements made by the telescope, even before its calibration and
data analysis software were finished.

"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!"

Kepler team members say these new data indicate the mission is indeed
capable of finding Earth-like planets, if they exist. 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 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 stove.

The Kepler measurements show the transit from the previously detected
HAT-P-7. However, these new measurements are so precise, they also
show a smooth rise and fall of the light between transits caused by
the changing phases of the planet, similar to those of our moon. This
is a combination of both the light emitted from the planet and the
light reflected off the planet. The smooth rise and fall of light is
also punctuated by a small drop in light, called an occultation,
exactly halfway between each transit. An occultation happens when a
planet passes behind a star.

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.

This new discovery also demonstrates Kepler has the precision to find
Earth-size planets. 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."

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.

For images, animations and more information about the Kepler mission,
visit:

http://www.nasa.gov/kepler