Kepler's five initial planet discoveries last year — named Kepler 4b, 5b, 6b, 7b and 8b — were announced Jan. 4, 2010 by the members of the Kepler science team during a news briefing at the American Astronomical Society meeting in Washington. They are all very hot, inhospitable worlds.
Numbers of Kepler Candidates
Diagram showing the numbers of Kepler planet candidates of various sizes.
Locations of Kepler Candidates
This diagram shows the Kepler field of view with locations of planet candidates color coded by size of planet.
Kepler-11 is a small, cool star around which six planets orbit
At times, two or more planets pass in front of the star at once, as shown in this artist's conception of a simultaneous transit of three planets observed by NASA's Kepler spacecraft on Aug. 26, 2010. "Kepler-11 is a remarkable system whose architecture and dynamics provide clues about its formation," said Jack Lissauer, a planetary scientist and Kepler science team member at Ames.
"These six planets are mixtures of rock and gases, possibly including water. The rocky material accounts for most of the planets' mass, while the gas takes up most of their volume. By measuring the sizes and masses of the five inner planets, we determined they are among the lowest mass confirmed planets beyond our solar system."
Kepler-11 Planet Sizes
Diagram showing relative sizes of all confirmed Kepler planet discoveries as of 2011 Feb 2, and comparison with Earth and Jupiter.
Kepler-11 System Compared to Our Own Solar System
Kepler-11 has the fullest, most compact planetary system yet discovered beyond our own. All six planets orbiting Kepler-11 are larger than Earth, with the largest ones being comparable in size to Uranus and Neptune. If placed in our solar system, the outermost planet would orbit between Mercury and Venus, and the other five planets would orbit between Mercury and our sun. The innermost planet, Kepler-11b, is ten times closer to its star than Earth is to the sun.
This artist¹s conception shows the Kepler-11 planetary system and our solar system from a tilted perspective to demonstrate that the orbits of each system are nearly circular and lie on similar planes.
Planet Kepler-10b in Orbit (Artist's Depiction)
Planet Kepler-10b is the smallest exoplanet (a planet located outside our solar system) discovered to date. All of Kepler’s best capabilities have converged to yield the first solid evidence of a solid planet orbiting a star other than our Sun. Knowledge of the planet is only as good as the knowledge of the star it orbits. Scientists of the Kepler Asteroseismic Science Consortium (KASC) were able to detect high frequency variations in the star’s brightness generated by stellar oscillations, or “starquakes.”
Data arising from light waves that travel within the interior of the star lead to better understanding of the star, just as earthquakes are used to learn about the interior structure of Earth. As a result of this analysis, Kepler-10 is one of the most well characterized planet-hosting stars in the universe next to the Sun. This analysis also allowed scientists to pin down the properties of Kepler-10b. It is unequivocally a rocky planet, with a surface you could stand on, a mass 4.6 times that of Earth, a diameter 1.4 times that of Earth, and an average density of 8.8 grams per cubic centimeter -- similar to that of an iron dumbbell.
A Scorched World, Kepler-10b (Artist's Depiction)
Kepler-10b is a scorched world, orbiting at a distance that’s more than 20 times closer to its star than Mercury is to our own Sun. The daytime temperature’s expected to be more than 2,500 degrees Fahrenheit, hotter than lava flows here on Earth. Intense radiation from the star has kept the planet from holding onto an atmosphere. Flecks of silicates and iron may be boiled off a molten surface and swept away by the stellar radiation, much like a comet’s tail when its orbit brings it close to the Sun.
Planet Kepler-10b Transiting Its Host Star (Artist's Depiction)
Kepler-10b orbits one of the 150,000 stars that the spacecraft is monitoring between the constellations of Cygnus and Lyra. We aim our mosaic of 42 detectors there, under the swan’s wing, just above the plane of the Milky Way galaxy. The star itself is very similar to our own sun in temperature, mass and size, but older with an age of over 8 billion years, compared to the 4-and-1/2 billion years of our own sun. It’s a quiet star, slowly spinning with a weak magnetic field and few of the sun spots that characterize our own sun.
The star’s about 560 light years from our solar system and one of the brighter stars that Kepler is monitoring. It was the first we identified as potentially harboring a very small transiting planet. The transits of the planet were first seen in July of 2009. The diameter of Kepler 10b is only about 1.4 times the diameter of Earth and it's mass is about 4.5 times that of Earth. It is the best example of a rocky planet to date.
An Imagined Canyon on Planet Kepler-10b (Artist's Depiction)
Many years ago, before Kepler launched, members of what became the Kepler team built a robotic telescope at Lick Observatory to learn to do transit photometry--detecting drops in brightness of stars when planets pass in front of them. We called it the “Vulcan Telescope,” named after the hypothetical planet that scientists in the 1800’s thought might exist between the Sun and Mercury.
A planet that might explain the small deviations in Mercury’s orbit that were later explained with Einstein’s theory of general relativity. Vulcan is the god of fire in Roman mythology, a name befitting of a world so close to the Sun. The artist’s rendering of Kepler-10b is reminiscent of that hypothetical planet Vulcan. The Kepler team came full circle in its quest. We know that we’ve only begun to imagine the possibilities.
Imagined View from Planet Kepler-10b (Artist's Depiction)
Kepler-10b orbits one of the 150,000 stars that the Kepler spacecraft is monitoring, a star that is very similar to our own Sun in temperature, mass and size, but older with an age of over 8 billion years, compared to the 4-and-1/2 billion years of our own Sun. It’s one of the brighter stars that Kepler is monitoring and about 560 light years from our solar system, which means when the light from this star began its journey toward Earth, European navigators were crossing the Atlantic Ocean for the first time in search of new horizons. Today, we’re still exploring and our crow’s nest is a space telescope called Kepler.
One day, the oceans we cross will be the galaxy itself, but for now, we imagine the worlds we discover by putting all that we’ve learned from our observations and analyses into the fingers of artists. Kepler-10b must be a scorched world, orbiting at a distance that’s more than 20 times closer to its star than Mercury is to our own Sun, with a daytime temperature expected to be more than 2,500 degrees Fahrenheit. The Kepler team has determined that Kepler-10b is a rocky planet, with a surface you could stand on, a mass 4.6 times that of Earth, anda diameter 1.4 times that of Earth.
Worlds on the Edge
This artist’s concept illustrates the two Saturn-sized planets discovered by NASA’s Kepler mission. The star system is oriented edge-on, as seen by Kepler, such that both planets cross in front, or transit, their star, named Kepler-9. This is the first star system found to have multiple transiting planets.
Dec. 18: An eight-billion-year-old cluster of stars 13,000 light-years from Earth, called NGC 6791, lies in Kepler's field of view. 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.
Dec. 18: 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. At the center of the field is a star with a known "hot Jupiter" planet, named TrES-2, zipping closely around it every 2.5 days. Kepler will observe TrES-2 and other known planets as a test to demonstrate that it is working properly, and to obtain new information about those planets.
This is Kepler's field of view superimposed on the night sky. The space telescope will examine an expansive, 100-square-degree patch of sky in our Milky Way galaxy.
March 6: Spectators watch the launch of NASA's planet-hunting spacecraft, Kepler, from Cocoa Beach, Fla. Launch occurred at 10:49 p.m. EST, sending the agency's first planet-hunting spacecraft on a three-and-a-half-year mission to seek signs of other Earth-like planets.
March 6: The Delta II rocket carrying NASA's Kepler spacecraft lifted off from Launch Complex 17-B at Cape Canaveral Air Force Station in Florida. Launch occurred at 10:49 p.m. EST, sending the agency's first planet-hunting spacecraft on a three-and-a-half-year mission to seek signs of other Earth-like planets.
Nov. 10, 2008: Kepler's solar array is assembled. Here we see a view of the backside of the solar array on the left. The spacecraft and photometer without the sunshade are shown on the right.
NASA's Kepler Space Telescope has one primary mission: to find Earth-size and smaller planets around other stars. And it's already found some amazing things.