Johannes Kepler was a German astronomer, mathematician, and astrologer. He is a key figure in the 17th-century scientific revolution, best known for his laws of planetary motion, and his books Astronomia nova, Harmonices Mundi, and Epitome Astronomiae Copernicanae. These works also provided one of the foundations for Newton's theory of universal gravitation.
A terrestrial planet, telluric planet, or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun, i.e. Mercury, Venus, Earth, and Mars. The terms "terrestrial planet" and "telluric planet" are derived from Latin words for Earth, as these planets are, in terms of structure, "Earth-like". These planets are located between the Sun and the Asteroid Belt.
Kepler is a retired space telescope launched by NASA to discover Earth-size planets orbiting other stars. Named after astronomer Johannes Kepler, the spacecraft was launched on March 7, 2009, into an Earth-trailing heliocentric orbit. The principal investigator was William J. Borucki. After nine years of operation, the telescope's reaction control system fuel was depleted, and NASA announced its retirement on October 30, 2018.
Sudarsky's classification of gas giants for the purpose of predicting their appearance based on their temperature was outlined by David Sudarsky and colleagues in the paper Albedo and Reflection Spectra of Extrasolar Giant Planets and expanded on in Theoretical Spectra and Atmospheres of Extrasolar Giant Planets, published before any successful direct or indirect observation of an extrasolar planet atmosphere was made. It is a broad classification system with the goal of bringing some order to the likely rich variety of extrasolar gas-giant atmospheres.
A circumbinary planet is a planet that orbits two stars instead of one.
Because of the short orbits of some binary stars, the only stable orbits for planets are outside the orbit of the two stars. New studies showed that there is a strong hint that the planet and stars originate from a single disk.
Kepler-39 is an F-type main sequence star located in the constellation Cygnus. It is located about 3,560 light-years away. One known substellar companion orbits it, Kepler-39b.
Kepler-20 is a star 929 light-years from Earth in the constellation Lyra with a system of five known planets. The apparent magnitude of this star is 12.51, so it cannot be seen with the unaided eye. Viewing it requires a telescope with an aperture of 15 cm (6 in) or more. It is slightly smaller than the Sun, with 94% of the Sun's radius and about 91% of the Sun's mass. The effective temperature of the photosphere is slightly cooler than that of the Sun at 5466 K, giving it the characteristic yellow hue of a stellar class G8 star. The abundance of elements other than hydrogen or helium, what astronomers term the metallicity, is approximately the same as in the Sun. It may be older than the Sun, although the margin of error here is relatively large.
Kepler-35 is a binary star system in the constellation of Cygnus. These stars, called Kepler-35A and Kepler-35B have masses of 89% and 81% solar masses respectively, therefore both are spectral class G. They are separated by 0.176 AU, and complete an eccentric orbit around a common center of mass every 20.73 days.
Maximilian Kepler-Różycki is a German professional baseball outfielder for the Minnesota Twins of Major League Baseball (MLB). He made his MLB debut in 2015. Before signing with the Twins, he played for Buchbinder Legionäre Regensburg of Bundesliga. He is left-handed.
Kepler-62f is a super-Earth exoplanet 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 990 light-years from Earth in the constellation of Lyra.
Kepler-38 is a binary star system. These stars, called Kepler-38A and Kepler-38B have masses of 95% and 25% solar masses respectively. The brighter star is spectral class G while the secondary has spectral class M. They are separated by 0.147 AU, and complete an eccentric orbit around a common center of mass every 18.8 days.
Kepler-90 is a G-type main sequence star located about 2,840 light-years (870 pc) from Earth in the constellation of Draco. It is notable for possesing a planetary system that has the same number of observed planets as the Solar System.
Kepler-186 is a main-sequence M1-type dwarf star, located 178.5 parsecs away in the constellation of Cygnus. The star is slightly cooler than the sun, with roughly half its metallicity. It is known to have five planets, including the first Earth-sized world discovered in the habitable zone: Kepler-186f. The star hosts four other planets discovered so far, though Kepler-186 b, c, and d are too close, but e is near the habitable zone's inner edge.
Kepler-186f (also known by its Kepler Object of Interest designation KOI-571.05) is an exoplanet orbiting the red dwarf Kepler-186, about 582 light-years (178.5 parsecs, or nearly 5.298×1015 km) from the Earth.
It is the first planet with a radius similar to Earth's to be discovered in the habitable zone of another star. NASA's Kepler space telescope detected it using the transit method, along with four additional planets orbiting much closer to the star (all modestly larger than Earth). Analysis of three years of data was required to find its signal. The results were presented initially at a conference on 19 March 2014 and some details were reported in the media at the time. The public announcement was on 17 April 2014, followed by publication in Science.
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-444 is a star, estimated to be 11.2 billion years old, approximately 116 light-years (36 pc) away from Earth in the constellation Lyra. On 27 January 2015, the Kepler spacecraft is reported to have confirmed the detection of five sub-Earth-sized rocky exoplanets orbiting the star. According to NASA, no life as we know it could exist on these hot exoplanets, due to their close orbital distances to the host star.
