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April 16th, 2009

Early Returns of Kepler's Hi-Tech Hunt In Search of Planets Like Earth


Photos are in from NASA's Kepler mission revealing the beautiful Milky Way galaxy and some eight billion year old cluster of stars. NASA's Kepler mission has taken its first images of the star-rich sky where it will soon begin hunting for planets like Earth.

The new "first light" images show the mission's target patch of sky, a vast starry field in the Cygnus-Lyra region of our Milky Way galaxy. One image shows millions of stars in Kepler's full field of view, while two others zoom in on portions of the larger region.

Kepler's stars This image zooms into a small portion of Kepler's full field of view — an expansive, 100-square-degree patch of sky in our Milky Way galaxy. An eight-billion-year-old cluster of stars 13,000 light-years from Earth, called NGC 6791, can be seen in the image. Clusters are families of stars that form together out of the same gas cloud. This particular cluster is called an open cluster, because the stars are loosely bound and have started to spread out from each other.

The area pictured is 0.2 percent of Kepler's full field of view, and shows hundreds of stars in the constellation Lyra. The image has been color-coded so that brighter stars appear white, and fainter stars, red. It is a 60-second exposure, taken on April 8, 2009, one day after the spacecraft's dust cover was jettisoned.

Kepler was designed to hunt for planets like Earth. The mission will spend the next three-and-a-half years staring at the same stars, looking for periodic dips in brightness. Such dips occur when planets cross in front of their stars from our point of view in the galaxy, partially blocking the starlight.

To achieve the level of precision needed to spot planets as small as Earth, Kepler's images are intentionally blurred slightly. This minimizes the number of saturated stars. Saturation, or "blooming," occurs when the brightest stars overload the individual pixels in the detectors, causing the signal to spill out into nearby pixels. Image credit: NASA/JPL-Caltech


"Kepler's first glimpse of the sky is awe-inspiring," said Lia LaPiana, Kepler's program executive at NASA Headquarters in Washington. "To be able to see millions of stars in a single snapshot is simply breathtaking."

One new image from Kepler shows its entire field of view — a 100-square-degree portion of the sky, equivalent to two side-by-side dips of the Big Dipper. The regions contain an estimated 14 million stars, more than 100,000 of which were selected as ideal candidates for planet hunting.

Two other views focus on just one-thousandth of the full field of view. In one image, a cluster of stars located about 13,000 light-years from Earth, called NGC 6791, can be seen in the lower left corner. The other image zooms in on a region containing a star, called Tres-2, with a known Jupiter-like planet orbiting every 2.5 days.

"It's thrilling to see this treasure trove of stars," said William Borucki, science principal investigator for Kepler at NASA's Ames Research Center at Moffett Field, California. "We expect to find hundreds of planets circling those stars, and for the first time, we can look for Earth-size planets in the habitable zones around other stars like the sun."

Kepler will spend the next three-and-a-half years searching more than 100,000 pre-selected stars for signs of planets. It is expected to find a variety of worlds, from large, gaseous ones, to rocky ones as small as Earth. The mission is the first with the ability to find planets like ours — small, rocky planets orbiting sun-like stars in the habitable zone, where temperatures are right for possible lakes and oceans of water.

To find the planets, Kepler will stare at one large expanse of sky for the duration of its lifetime, looking for periodic dips in starlight that occur as planets circle in front of their stars and partially block the light. Its 95-megapixel camera, the largest ever launched into space, can detect tiny changes in a star's brightness of only 20 parts per million. Images from the camera are intentionally blurred to minimize the number of bright stars that saturate the detectors. While some of the slightly saturated stars are candidates for planet searches, heavily saturated stars are not.

"Everything about Kepler has been optimized to find Earth-size planets," said James Fanson, Kepler's project manager at NASA's Jet Propulsion Laboratory in Pasadena, California. "Our images are road maps that will allow us, in a few years, to point to a star and say a world like ours is there."

Scientists and engineers will spend the next few weeks calibrating Kepler's science instrument, the photometer, and adjusting the telescope's alignment to achieve the best focus. Once these steps are complete, the planet hunt will begin.

"We've spent years designing this mission, so actually being able to see through its eyes is tremendously exciting," said Eric Bachtell, the lead Kepler systems engineer at Ball Aerospace & Technology Corp. in Boulder, Colorado. Bachtell has been working on the development and testing of Kepler for nine years.

Kepler is a NASA Discovery mission. Ames is responsible for the ground system development, mission operations and science data analysis. JPL manages the Kepler mission development. Ball Aerospace & Technologies Corp. is responsible for developing the Kepler flight system and supporting mission operations.

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