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Home > Missions > Kepler
Introduction Kepler
Are there planets orbiting other stars with characteristics similar to Earth? In recent years, scientists have discovered nearly 400 stars with orbiting giant planets. The challenge is to find terrestrial planets, those one-half to twice the size of the Earth, and especially those in the "habitable zone" of their stars where liquid water and possibly life might exist. We might soon find answers with Kepler - the first mission capable of detecting Earth-size and smaller planets in or near the habitable zone. Mission Management
Dr. William Borucki,
Science Principal Investigator The operations phase of the Kepler mission is managed for NASA by the Ames Research Center, Moffett Field, CA. NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA, managed the mission through development, launch and the start of science operations. Dr. William Borucki of NASA Ames is the mission's Science Principal Investigator. Ball Aerospace and Technologies Corp., Boulder, CO, developed the Kepler flight system.
In October 2009, oversight of the Kepler project was transferred from the Discovery Program at NASA's Marshall Space Flight Center, Huntsville, AL, to the Exoplanet Exploration Program at JPL. Science Objectives
The scientific objective of the Kepler Mission is to explore the structure and diversity of extrasolar planetary systems with a special emphasis on the detection of Earth-size planets. The results will yield a broad understanding of planetary formation, the frequency of formation, the structure of individual planetary systems, and the generic characteristics of stars with terrestrial planets.
Launched on March 6, 2009, the Kepler instrument is a specially designed 0.95-meter diameter telescope called a photometer, a device that measures the brightness of light. It has the largest camera ever launched into space, a 95-megapixel array of charge-coupled devices, or CCDs, like those in digital cameras. It has a very large field of view, allowing it to focus on the same huge star field for the entire mission and continuously monitor the brightness of more than 100,000 stars. When a planet passes in front of a star as viewed from Earth, the event is called a "transit." From Earth, Venus or Mercury transits look like a small black dot creeping across the Sun as the planet moves between the Sun and Earth. Kepler finds planets by looking for tiny dips in the brightness of a star when a planet crosses in front of it. This transit of planets across the faces of stars will be recorded by sensors on the Kepler photometer and will provide raw data which will lead to the determination of the planet's size and the orbital period. From the orbital size and the temperature of the star, the planet's characteristic temperature can be calculated, indicating whether or not the planet is in the habitable zone.
Kepler photometer being lowered onto spacecraft.
The Kepler science team announced its first exoplanet discoveries in January 2010. The five new exoplanets were discovered from Kepler's first 43 days of data. Known as "hot Jupiters" because of their high masses and extreme temperatures, the new exoplanets range in size from similar to Neptune to larger than Jupiter. Estimated temperatures of the planets range from 2,200 to 3,000° F, hotter than molten lava and much too hot for life as we know it. All five of the exoplanets orbit stars that are hotter and larger than our Sun.
Kepler's high sensitivity to both small and large planets enabled the discovery of these exoplanets. The observations contribute to our understanding of how planetary systems form and evolve from the gas and dust disks that give rise to both the stars and their planets, and the discoveries show that the science instrument is working well.
Three more planet discoveries were confirmed in August 2010. Kepler discovered two new Saturn-sized planets and a possible third planet 1-1/2 times bigger than Earth orbiting a star over 2,200 light years away in the constellation Lyra. The discovery is the first confirmed planetary system with more than one planet crossing in front of, or transiting, the same star.
Kepler confirmed the discovery of its first rocky planet, named Kepler-10b, in January 2011. Measuring 1.4 times the size of Earth, it is the smallest planet ever discovered outside our solar system. In February 2011, Kepler announced the discovery of six planets made of a mix of rock and gases orbiting a single sun-like star known as Kepler-11, located about 2,000 light years from Earth. It's the fullest, most compact planetary system yet discovered beyond our own. All the planets are larger than Earth, closer to the size of Uranus and Neptune, and five of the six orbit closer to their star than any in our solar system.
Kepler's groundbreaking discovery of a planet orbiting two stars, announced in September 2011, was the first unambiguous detection of a circumbinary planet. This discovery confirmed a theory that scientists had for decades but could not prove until until.
Follow Kepler's discoveries here.
Kepler's first five planet discoveries.
Artist's concept of a world with two sunsets, discovered by Kepler. The smaller sun, a red dwarf, circles the larger star, a K dwarf, while the strange new planet orbits them both. The alignment of the orbits of the stars and the planet within a degree of each other indicate that the planet formed within the same circumbinary disk that the stars formed within, rather than being captured later by the two stars. Credit: NASA/JPL-Caltech/R. Hurt Noteworthy
In 1977, the existence of a world with a double sunset was portrayed in the classic space fantasy film "Star Wars." In September 2011, that intriguing science fiction concept became now scientific fact, thanks to NASA's Kepler mission. As part of its ongoing observation of transits as it searches for Earth-size planets around other stars, Kepler detected a planet, known as Kepler 16B, that orbits two stars 200 light years from Earth. Unlike Star Wars' Tatooine, the home planet of Luke Skywalker, the real planet is an inhospitable, cold world about the size ofSaturn, thought to be made up of rock and gas. This first discovery of a planet orbiting two stars, called a circumbinary star, demonstrates the diversity of planets in our galaxy. Previous research hinted at the existence of circumbinary planets, but it could not be confirmed until now. "This discovery confirms a new class of planetary systems that could harbor life," Kepler principal investigator William Borucki said. "Given that most stars in our galaxy are part of a binary system, this means the opportunities for life are much broader than if planets form only around single stars. This milestone discovery confirms a theory that scientists have had for decades but could not prove until now."
Artist's impression of the two Saturn-size planets in the Kepler 9 system. Credit: NASA/Ames/JPL-Caltech
NASA Official: Brian Mitchell
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