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2204 Lyyli
2204 Lyyli (Minor planet provisional designation, ''prov. designation'': ) is a dark asteroid and very eccentric Mars-crosser from the middle region of the asteroid belt, approximately in diameter. It was discovered on 3 March 1943 by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland. Orbit and classification ''Lyyli'' orbits the Sun in the Kirkwood gap, central main-belt at a distance of 1.5–3.6 Astronomical unit, AU once every 4 years and 2 months (1,522 days). Its orbit has an orbital eccentricity, eccentricity of 0.41 and an orbital inclination, inclination of 21Degree (angle), ° with respect to the ecliptic. Naming This minor planet was named in honour of Lyyli Heinänen (1903–1988), née Hartonen, a Finnish female Esperantist, professor of mathematics, amateur astronomer and former assistant of the discoverer. The official naming citation was published by the Minor Planet Center on 26 May 1983 (). Physical characteristics '' ...
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Lightcurve
In astronomy, a light curve is a graph (discrete mathematics), graph of the Radiance, light intensity of a celestial object or region as a function of time, typically with the magnitude (astronomy), magnitude of light received on the ''y''-axis and with time on the ''x''-axis. The light is usually in a particular frequency interval or frequency band, band. Light curves can be periodic, as in the case of eclipsing binary, eclipsing binaries, Cepheid variables, other periodic variables, and Methods of detecting extrasolar planets#Transit photometry, transiting extrasolar planets; or aperiodic, like the light curve of a nova, cataclysmic variable star, supernova, gravitational microlensing, microlensing event, or binary as observed during occultation events. The study of a light curve and other observations can yield considerable information about the physical process that produces such a light curve, or constrain the physical theories about it. Variable stars Graphs of the ap ...
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Kirkwood Gap
A Kirkwood gap is a gap or dip in the distribution of the semi-major axes (or equivalently of the orbital periods) of the orbits of main-belt asteroids. They correspond to the locations of orbital resonances with Jupiter. The gaps were first noticed in 1866 by Daniel Kirkwood, who also correctly explained their origin in the orbital resonances with Jupiter while a professor at Jefferson College in Canonsburg, Pennsylvania. For example, there are very few asteroids with semimajor axis near 2.50 AU, period 3.95 years, which would make three orbits for each orbit of Jupiter (hence, called the 3:1 orbital resonance). Other orbital resonances correspond to orbital periods whose lengths are simple fractions of Jupiter's. The weaker resonances lead only to a depletion of asteroids, while spikes in the histogram are often due to the presence of a prominent asteroid family ''(see List of asteroid families)''. Most of the Kirkwood gaps are depleted, unlike the mean-motion resonance ...
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132 Aethra
132 Aethra is a metallic asteroid and Mars-crosser on an eccentric orbit from the asteroid belt. It measures approximately 40 kilometers in diameter. It was discovered by James Craig Watson in 1873 and is the first such Mars-crosser asteroid to be identified. As a Mars-crosser asteroid, Aethra is the lowest numbered asteroid to not have proper orbital elements due to recurring perturbations by Mars. It has a rather eccentric orbit that sometimes brings it closer to the Sun than the planet Mars. With an original observation arc of only 22 days, 132 Aethra was a lost asteroid between 1873 and 1922. The varying light curve of the asteroid implies an elongated or irregular shape for its body. It is named after Aethra, the mother of Theseus in Greek mythology Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of ancient Greek folklore, today absorbed alongside Roman mythology into the broader designation of classical ...
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Wide-field Infrared Survey Explorer
Wide-field Infrared Survey Explorer (WISE, List of observatory codes, observatory code C51, Explorer 92 and MIDEX-6) was a NASA infrared astronomy Space observatory, space telescope in the Explorers Program launched in December 2009.. . WISE List of minor planet discoverers#WISE, discovered thousands of minor planets and numerous star clusters. Its observations also supported the discovery of the first Y dwarf, Y-type brown dwarf and Earth trojan, Earth trojan asteroid. ... . WISE performed an all-sky astronomical survey with images in 3.4, 4.6, 12 and 22 μm wavelength range bands, over ten months using a diameter infrared telescope in Geocentric orbit, Earth orbit. After its solid hydrogen coolant depleted, it was placed in Hibernation (spaceflight), hibernation mode in February 2011. In 2013, NASA reactivated the WISE telescope to search for near-Earth objects (NEO), such as comets and asteroids, that could collide with Earth. The reactivation mission was called Near-Eart ...
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Akari (satellite)
AKARI (ASTRO-F) was an infrared astronomy satellite developed by Japan Aerospace Exploration Agency, in cooperation with institutes of Europe and Korea. It was launched on 21 February 2006, at 21:28 UTC (06:28, 22 February JST) by M-V rocket into Earth Sun-synchronous orbit. After its launch it was named ''AKARI'' (明かり), which means ''light'' in Japanese. Earlier on, the project was known as IRIS (InfraRed Imaging Surveyor). Its primary mission was to survey the entire sky in near-, mid- and far-infrared, through its aperture telescope. Technical design Its designed lifespan, of far- and mid-infrared sensors, was 550 days, limited by its liquid helium coolant. Its telescope mirror was made of silicon carbide to save weight. The budget for the satellite was ¥13,4 billion (~). History By mid-August 2006, AKARI finished around 50 per cent of the all sky survey. By early November 2006, first (phase-1) all-sky survey finished. Second (phase-2) all-sky survey starte ...
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Astronomical Albedo
Albedo ( ; ) is the fraction of sunlight that is diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects all incident radiation). ''Surface albedo'' is defined as the ratio of radiosity ''J''e to the irradiance ''E''e (flux per unit area) received by a surface. The proportion reflected is not only determined by properties of the surface itself, but also by the spectral and angular distribution of solar radiation reaching the Earth's surface. These factors vary with atmospheric composition, geographic location, and time (see position of the Sun). While directional-hemispherical reflectance factor is calculated for a single angle of incidence (i.e., for a given position of the Sun), albedo is the directional integration of reflectance over all solar angles in a given period. The temporal resolution may range from seconds (as obtained from flux measurements) to ...
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Rotation Period
In astronomy, the rotation period or spin period of a celestial object (e.g., star, planet, moon, asteroid) has two definitions. The first one corresponds to the '' sidereal rotation period'' (or ''sidereal day''), i.e., the time that the object takes to complete a full rotation around its axis relative to the background stars ( inertial space). The other type of commonly used "rotation period" is the object's '' synodic rotation period'' (or ''solar day''), which may differ, by a fraction of a rotation or more than one rotation, to accommodate the portion of the object's orbital period around a star or another body during one day. Measuring rotation For solid objects, such as rocky planets and asteroids, the rotation period is a single value. For gaseous or fluid bodies, such as stars and giant planets, the period of rotation varies from the object's equator to its pole due to a phenomenon called differential rotation. Typically, the stated rotation period for a giant pl ...
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NEOWISE
Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and MIDEX-6) was a NASA infrared astronomy space telescope in the Explorers Program launched in December 2009.. . WISE discovered thousands of minor planets and numerous star clusters. Its observations also supported the discovery of the first Y-type brown dwarf and Earth trojan asteroid. ... . WISE performed an all-sky astronomical survey with images in 3.4, 4.6, 12 and 22 μm wavelength range bands, over ten months using a diameter infrared telescope in Earth orbit. After its solid hydrogen coolant depleted, it was placed in hibernation mode in February 2011. In 2013, NASA reactivated the WISE telescope to search for near-Earth objects (NEO), such as comets and asteroids, that could collide with Earth. The reactivation mission was called Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE). As of August 2023, NEOWISE was 40% through the 20th coverage of the full sky. Science o ...
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Minor Planet Circulars
The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function The Minor Planet Center is the official worldwide organization in charge of collecting observational data for minor planets (such as asteroids), calculating their orbits and publishing this information via the '' Minor Planet Circulars''. Under the auspices of the International Astronomical Union (IAU), it operates at the Smithsonian Astrophysical Observatory, which is part of the Center for Astrophysics along with the Harvard College Observatory. The MPC runs a number of free online services for observers to assist them in observing minor planets and comets. The complete catalogue of minor planet orbits (sometimes referred to as the "Minor Planet Catalogue") may also be freely downloaded. In addition to astrometric data, the MPC coll ...
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Minor Planet Center
The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function The Minor Planet Center is the official worldwide organization in charge of collecting observational data for minor planets (such as asteroids), calculating their orbits and publishing this information via the '' Minor Planet Circulars''. Under the auspices of the International Astronomical Union (IAU), it operates at the Smithsonian Astrophysical Observatory, which is part of the Center for Astrophysics along with the Harvard College Observatory. The MPC runs a number of free online services for observers to assist them in observing minor planets and comets. The complete catalogue of minor planet orbits (sometimes referred to as the "Minor Planet Catalogue") may also be freely downloaded. In addition to astrometric data, the ...
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Lyyli Heinänen
2204 Lyyli ( ''prov. designation'': ) is a dark asteroid and very eccentric Mars-crosser from the middle region of the asteroid belt, approximately in diameter. It was discovered on 3 March 1943 by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland. Orbit and classification ''Lyyli'' orbits the Sun in the central main-belt at a distance of 1.5–3.6  AU once every 4 years and 2 months (1,522 days). Its orbit has an eccentricity of 0.41 and an inclination of 21 ° with respect to the ecliptic. Naming This minor planet was named in honour of Lyyli Heinänen (1903–1988), née Hartonen, a Finnish female Esperantist, professor of mathematics, amateur astronomer and former assistant of the discoverer. The official naming citation was published by the Minor Planet Center on 26 May 1983 (). Physical characteristics ''Lyyli'' is an X-type asteroid in the SMASS classification. It has also been characterized as a P-type asteroid by NASA's ...
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Minor Planet
According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor planet'', but that year's meeting IAU definition of planet, reclassified minor planets and comets into dwarf planets and Small Solar System body, small Solar System bodies (SSSBs).Press release, IAU 2006 General Assembly: Result of the IAU Resolution votes
International Astronomical Union, August 24, 2006. Accessed May 5, 2008.
In contrast to the eight official planets of the Solar System, all minor planets fail to clearing the neighborhood, clear their orbital neighborhood. Minor planets include asteroids (near- ...
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