In astronomy, Kepler's laws of planetary motion, published by Johannes Kepler between 1609 and 1619, describe the orbits of planets around the Sun. The laws modified the heliocentric theory of Nicolaus Copernicus, replacing its circular orbits and epicycles with elliptical trajectories, and explaining how planetary velocities vary. The three laws state that:
- The orbit of a planet is an ellipse with the Sun at one of the two foci.
- A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.
- The square of a planet's orbital period is proportional to the cube of the length of the semi-major axis of its orbit.
The Eddington mission was a European Space Agency (ESA) project that planned to search for Earth-like planets, but was cancelled in 2003. It was named for Arthur Eddington, a noted physicist who translated Albert Einstein's work and carried out the first test of the general theory of relativity. It was originally planned for operation in 2008, but was delayed. The ESA website now records its status as cancelled.
Kepler-5 is a star located in the constellation Cygnus in the field of view of the Kepler Mission, a NASA project aimed at detecting planets in transit of, or passing in front of, their host stars as seen from Earth. One closely orbiting, Jupiter-like planet, named Kepler-5b, has been detected around Kepler-5. Kepler-5's planet was one of the first five planets to be discovered by the Kepler spacecraft; its discovery was announced on January 4, 2010 at the 215th meeting of the American Astronomical Society after being verified by a variety of observatories. Kepler-5 is larger and more massive than the Sun, but has a similar metallicity, a major factor in planet formation.
Kepler-10, formerly known as KOI-72, is a Sun-like star in the constellation of Draco that lies 187 parsecs from Earth. Kepler-10 was targeted by NASA's Kepler spacecraft, as it was seen as the first star identified by the Kepler mission that could be a possible host to a small, transiting exoplanet. The star is slightly less massive, slightly larger, and slightly cooler than the Sun; at an estimated 10.4 billion years in age, Kepler-10 is almost 2.6 times the age of the Sun. Kepler-10 is host to a planetary system made up of at least two planets. Kepler-10b, the first undeniably rocky planet, was discovered in its orbit after eight months of observation and announced on January 10, 2011. The planet orbits its star closely, completing an orbit every 0.8 days, and has a density similar to that of iron. The second planet, Kepler-10c, was confirmed on May 23, 2011, based on follow-up observations by the Spitzer Space Telescope. The data shows it has an orbital period of 42.3 days and has a radius more than double that of Earth, but a higher density, making it the largest and most massive rocky planet discovered as of June 2014.
Kepler-10c is an exoplanet orbiting the G-type star Kepler-10, located around 608 light-years away in Draco. Its discovery was announced by Kepler in May 2011, although it had been seen as a planetary candidate since January 2011, when Kepler-10b was discovered. The team confirmed the observation using data from NASA's Spitzer Space Telescope and a technique called BLENDER that ruled out most false positives. Kepler-10c was the third transiting planet to be confirmed statistically, after Kepler-9d and Kepler-11g. The Kepler team considers the statistical method that led to the discovery of Kepler-10c as what will be necessary to confirm many planets in Kepler's field of view.
Kepler-69c is a confirmed super-Earth extrasolar planet, likely rocky, orbiting the Sun-like star Kepler-69, the outermore of two such planets discovered by NASA's Kepler spacecraft. It is located about 2,430 light-years from Earth.
Kepler-62 is a star somewhat cooler and smaller than the Sun in the constellation Lyra, 1200 light years from Earth. It is located within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission used to detect planets that may be transiting their stars. On April 18, 2013 it was announced that the star has five planets, two of which, Kepler-62e and Kepler-62f are within the star's habitable zone. The outermost, Kepler-62f, is likely a rocky planet.
Kepler-62f, which is also known by its Kepler Object of Interest designation KOI-701.04, is a super-Earth exoplanet. It is orbiting within the habitable zone of the star Kepler-62, the outermost of five such planets discovered around the star by NASA's Kepler spacecraft. It is located about 1200 light-years from Earth in the constellation of Lyra.
Kepler-69 is a G-type main-sequence star similar to the Sun in the constellation Cygnus, located about 2,430 ly (750 pc) from Earth. On April 18, 2013 it was announced that the star has two planets. Although initial estimates indicated that the terrestrial planet Kepler-69c might be within the star's habitable zone, further analysis showed that the planet very likely is interior to the habitable zone and is far more analogous to Venus than to Earth and thus completely inhospitable.
Kepler-78b is an exoplanet orbiting around the star Kepler-78. At the time of its discovery, it was the exoplanet most similar to Earth in terms of mass, radius and mean density.
Kepler-442b is a confirmed near-Earth-sized exoplanet, likely rocky, orbiting within the habitable zone of the K-type main-sequence star Kepler-442, about 1,206 light-years, from Earth in the constellation Lyra. The planet was discovered by NASA's Kepler spacecraft using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. NASA announced the confirmation of the exoplanet on 6 January 2015.
Kepler-452b is an exoplanet orbiting the Sun-like star Kepler-452 about 1,402 light-years (430 pc) from Earth in the constellation Cygnus. It was identified by the Kepler space telescope, and its discovery was announced by NASA on 23 July 2015. However, a study in 2018 by Mullally et al. implied that statistically, Kepler-452b has not been proven to exist and must still be considered a candidate. Moreover, its mass of 5 Earth masses increases the possibility that the planet is a mini-Neptune instead of a super-Earth. It is the first potentially rocky super-Earth planet discovered orbiting within the habitable zone of a star very similar to the Sun. The planet is about 1,400 light-years away from the Solar System. At the speed of the New Horizons spacecraft, about 59,000 km/h (37,000 mph), it would take approximately 26 million years to get there.
Kepler-371b is a confirmed Super-Earth sized exoplanet. Orbiting around the F-type star Kepler-371 every 35 days about 2720 ly away from the Earth.
Kepler-371 is a star some 2,720 ly away from the Earth. It hosts a multi planetary system consisting of 2 confirmed Super-Earths, as well as 1 unconfirmed Near-Earth sized exoplanet in its habitable zone.
2MASS J19383260+4603591 b also known as Kepler-451b is a circumbinary exoplanet orbiting the star 2MASS J19383260+4603591. It has a mass of 604±32 Earth Masses or 1.9±0.1 Jupiter Masses. It was discovered using Eclipse Timing Variations by the Kepler space telescope in 2015.
Kepler-277b is the second most massive and third-largest rocky planet ever discovered, with a mass close to that of Saturn. Discovered in 2014 by the Kepler Space Telescope, Kepler-277b is a sub-Neptune sized exoplanet with a very high mass and density for an object of its radius, suggesting a composition made mainly of rock and iron. Along with its sister planet, Kepler-277c, the planet's mass was determined using transit-timing variations (TTVs).
Kepler-277c is the third most massive and second-largest rocky planet ever discovered, with a mass about 64 times that of Earth. Discovered in 2014 by the Kepler Space Telescope, Kepler-277c is a Neptune-sized exoplanet with a very high mass and density for an object of its radius, suggesting a composition made mainly of rock with some amounts of water. Along with its sister planet, Kepler-277b, the planet's mass was determined using transit-timing variations (TTVs).
Kepler-1649c is an exoplanet orbiting the M-type main sequence red dwarf star Kepler-1649, about 300 light-years from Earth, in the constellation of Cygnus. In 2020, Jeff Coughlin, the director of SETI's K2 Science Office, described it as the most "similar planet to Earth" found so far by the Kepler Space Telescope. The planet was originally deemed a false positive by Kepler's robovetter algorithm. The Kepler False Positive Working Group published its recovery on April 15, 2020. Its first scientific description was published in The Astrophysical Journal Letters, with first author Andrew Vanderburg, in April 2020.
