Lexell's CometD/1770 L1, popularly known as Lexell's Comet after its orbit computer Anders Johan Lexell, was a comet discovered by astronomerCharles Messier in June 1770. It is notable for having passed closer to Earth than any other comet in recorded history, approaching to a distance of only 0.015 astronomical units (2,200,000 km; 1,400,000 mi), or six times the distance from the Earth to the Moon. The comet is lost, having not been seen since 1770.
Comet Swift–TuttleComet Swift–Tuttle (formally designated 109P/Swift–Tuttle) is a large periodic comet with a 1995 (osculating) orbital period of 133 years that is in a 1:11 orbital resonance with Jupiter. It fits the classical definition of a Halley-type comet, which has an orbital period between 20 and 200 years. The comet was independently discovered by Lewis Swift on 16 July 1862 and by Horace Parnell Tuttle on 19 July 1862. Its nucleus is 26 km (16 mi) in diameter.
Lost minor planetA minor planet is "lost" when contemporary observers cannot find it, because its location is too uncertain to target observations. This happens if the orbital elements of a minor planet are not known accurately enough, typically because the observation arc for the object is too short, or too few observations were made before the object became unobservable (e.g. too faint due to increasing distance, or too close to the Sun to view at night).
CometNatural object in space that releases gasA comet is an icy, small Solar System body or interstellar object that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or coma surrounding the nucleus, and sometimes a tail of gas and dust gas blown out from the coma.
Solar SystemPlanetary system consisting of the Sun and objects orbiting itThe Solar System is the gravitationally bound system of the Sun and the masses that orbit it, most prominently its eight planets, of which Earth is one. The Solar System is an isolated single-star planetary system (not part of a larger star system) within the Milky Way Galaxy.
Perturbation (astronomy)In astronomy, perturbation is the complex motion of a massive body subjected to forces other than the gravitational attraction of a single other massivebody. The other forces can include a third (fourth, fifth, etc.) body, resistance, as from an atmosphere, and the off-center attraction of an oblate or otherwise misshapen body. IntroductionThe study of perturbations began with the first attempts to predict planetary motions in the sky.
JupiterFifth planet from the SunApparent magnitude−2.94 to −1.66Absolute magnitude (H)−9.4Angular diameter29.8" to 50.1"AtmosphereSurface pressure200–600 kPa (30–90 psi)(opaque cloud deck)Scale height27 km (17 mi)Composition by volume89%±2.0%hydrogen10%±2.0%helium0.3%±0.1%methane0.026%±0.004%ammonia0.0028%±0.001%hydrogen deuteride0.0006%±0.0002%ethane0.0004%±0.0004%waterJupiter is the fifth planet from the Sun, and the largest in the Solar System.
Comet nucleusThe comet nucleus is the solid, central part of a comet. A cometary nucleus is composed of rock, dust, and frozen gases. When heated by the Sun, the gases sublime and produce an atmosphere surrounding the nucleus known as the coma. The force exerted on the coma by the Sun's radiation pressure and solar wind cause an enormous tail to form, which points away from the Sun. A typical comet nucleus has an albedo of 0.04.Brian G. MarsdenBrian Geoffrey Marsden (5 August 1937 – 18 November 2010) was a British astronomer and the longtime director of the Minor Planet Center (MPC) at the Center for Astrophysics | Harvard & Smithsonian (director emeritus from 2006 to 2010).
ApsisAn apsis (from Ancient Greek (hapsís)'arch, vault' (third declension); pl.apsides ) is one of the two extreme points in the orbit of a planetary body about its primary body, either the farthest point (apoapsis) or the nearest point (periapsis). The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two apsides. Apsides pertaining to orbits around different bodies have distinct names to differentiate themselves from other apsides.Extinct cometAn extinct comet is a comet that has expelled most of its volatile ice and has little left to form a tail and coma. In a dormant comet, rather than being depleted, any remaining volatile components have been sealed beneath an inactive surface layer. Due to the near lack of a coma and tail, an extinct or dormant comet may resemble an asteroid rather than a comet and blur the distinction between these two classes of small Solar System bodies.Elongation (astronomy)In astronomy, a planet's elongation is the angular separation between the Sun and the planet, with Earth as the reference point. The greatest elongation is the maximum angular separation. Astronomical tables and websites, such as Heavens-Above, forecast when and where the planets reach their next maximum elongations.*As an Amazon Associate I earn from qualifying purchases.