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52246 Donaldjohanson
52246 Donaldjohanson, provisional designation , is a carbonaceous Erigonian asteroid from the inner regions of the asteroid belt, approximately in diameter. It was discovered on 2 March 1981, by American astronomer Schelte Bus at the Siding Spring Observatory in Australia. The C-type asteroid is a target of the ''Lucy'' mission and was aptly named after American paleoanthropologist Donald Johanson. Orbit and classification Donaldjohanson is a member of the Erigone family (), a large carbonaceous asteroid family of nearly 2,000 known members, which is named after its parent body 163 Erigone. It is a relatively old family that was created approximately 130 million years ago. It orbits the Sun in the inner asteroid belt at a distance of 1.9–2.8 AU once every 3 years and 8 months (1,345 days; semi-major axis of 2.38 AU). Its orbit has an eccentricity of 0.19 and an inclination of 4 ° with respect to the ecliptic. A first precovery was taken at the discove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schelte Bus
Schelte John "Bobby" Bus (born 1956) is an American astronomer and discoverer of minor planets at the Institute for Astronomy (Hawaii), Institute for Astronomy of the University of Hawaii and deputy director of NASA's Infrared Telescope Facility (IRTF) at the Mauna Kea Observatory in Hawaii, United States. Biography Bus graduated in 1979 from Caltech with a BS. In 1999, he received his Ph.D. from the Massachusetts Institute of Technology. With MIT's Richard Binzel, Bus further added to the knowledge about main-belt asteroids in a spectroscopic survey published in 2002. This project was known as Small Main-Belt Asteroid Spectroscopic Survey, Phase II or SMASSII, which built on a previous survey of the main-belt asteroids. The visible-wavelength (435–925 nanometers) spectra data was gathered between August 1993 and March 1999. During his studies, he worked under the supervision of Eugene Shoemaker. As of 2017, Bus is an Astronomer at the University of Hawaii Institute for Astro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parent Body
In meteoritics, a parent body is the celestial body from which originates a meteorite or a class of meteorites. Identification The easiest way to correlate a meteorite with a parent body is when the parent body still exists. This is the case for Lunar and Martian meteorites. Samples from Lunar meteorites can be compared with samples from the Apollo program. Martian meteorites can be compared to analysis carried out by rovers (e.g. Curiosity). Meteorites can also be compared to spectral classes of asteroids. In order to identify the parent body of a class of meteorites, scientists compare their albedo and spectra with other known bodies. These studies show that some meteorite classes are closely related to some asteroids. The HED meteorites for example are correlated with 4 Vesta.Gunter Faure, Teresa M. Mensing. ''Introduction to Planetary Science: The Geological Perspective''Page 175 Another, perhaps most useful way to classify meteorites by parent bodies is by grouping t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binary System
A binary system is a system of two astronomical bodies which are close enough that their gravitational attraction causes them to orbit each other around a barycenter ''(also see animated examples)''. More restrictive definitions require that this common center of mass is not located within the interior of either object, in order to exclude the typical planet–satellite systems and planetary systems. The most common binary systems are binary stars and binary asteroid, but brown dwarfs, planets, neutron stars, black holes and galaxies can also form binaries. A ''multiple system'' is like a binary system but consists of three or more objects such as for trinary stars and trinary asteroids. Classification In a binary system, the brighter object is referred to as primary, and the other the secondary. They are also classified based on orbit. Wide binaries are objects with orbits that keep them apart from one another. They evolve separately and have very little effect on each ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnitude (astronomy)
In astronomy, magnitude is a unitless measure of the brightness Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception elicited by the luminance of a visual target. The perception is not linear to luminance, ... of an astronomical object, object in a defined passband, often in the visible spectrum, visible or infrared spectrum, but sometimes across all wavelengths. An imprecise but systematic determination of the magnitude of objects was introduced in ancient times by Hipparchus. The scale is Logarithmic scale, logarithmic and defined such that a magnitude 1 star is exactly 100 times brighter than a magnitude 6 star. Thus each step of one magnitude is \sqrt[5] \approx 2.512 times brighter than the magnitude 1 higher. The brighter an object appears, the lower the value of its magnitude, with the brightest objects reaching negative values. Astronomers use two different defini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lightcurve
In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the 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 band. Light curves can be periodic, as in the case of eclipsing binaries, Cepheid variables, other periodic variables, and transiting extrasolar planets, or aperiodic, like the light curve of a nova, a cataclysmic variable star, a supernova or a microlensing event or binary as observed during occultation events. The study of the light curve, together with other observations, can yield considerable information about the physical process that produces it or constrain the physical theories about it. Variable stars Graphs of the apparent magnitude of a variable star over time are commonly used to visualise and analyse their behaviour. Although the categorisation of variable star types is increasingly done from their spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Slow Rotators (minor Planets)
This is a list of slow rotators—minor planets that have an exceptionally long rotation period. This period, typically given in hours, and sometimes called rotation rate or spin rate, is a fundamental standard physical property for minor planets. In recent years, the periods of many thousands of bodies have been obtained from photometric and, to a lesser extent, radiometric observations. The periods given in this list are sourced from the ''Light Curve Data Base'' (LCDB), which contains lightcurve data for more than 15,000 bodies. Most minor planets have rotation periods between 2 and 20 hours. , a group of approximately 650 bodies, typically measuring 1–20 kilometers in diameter, have periods of more than 100 hours or 4 days. Among the slowest rotators, there are currently 15 bodies with a period longer than 1000 hours. According to the Minor Planet Center, the sharp lower limit of approximately 2.2 hours is due to the fact that most smaller bodies are thought to be ru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absolute Magnitude
Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it were viewed from a distance of exactly , without Extinction (astronomy), extinction (or dimming) of its light due to absorption by Interstellar medium, interstellar matter and cosmic dust. By hypothetically placing all objects at a standard reference distance from the observer, their luminosities can be directly compared among each other on a magnitude scale. As with all astronomical magnitude (astronomy), magnitudes, the absolute magnitude can be specified for different wavelength ranges corresponding to specified Filter (optics), filter bands or passbands; for stars a commonly quoted absolute magnitude is the absolute visual magnitude, which uses the visual (V) band of the spectrum (in the UBV phot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid Spectral Type
An asteroid spectral type is assigned to asteroids based on their emission spectrum, color, and sometimes albedo. These types are thought to correspond to an asteroid's surface composition. For small bodies that are not internally differentiated, the surface and internal compositions are presumably similar, while large bodies such as Ceres and Vesta are known to have internal structure. Over the years, there has been a number of surveys that resulted in a set of different taxonomic systems such as the Tholen, SMASS and Bus–DeMeo classifications. Taxonomic systems In 1975, astronomers Clark R. Chapman, David Morrison, and Ben Zellner developed a simple taxonomic system for asteroids based on color, albedo, and spectral shape. The three categories were labelled " C" for dark carbonaceous objects, " S" for stony (silicaceous) objects, and "U" for those that did not fit into either C or S. This basic division of asteroid spectra has since been expanded and clarified.Thomas H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Observation Arc
In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly used in the discovery and tracking of asteroids and comets. Arc length has the greatest influence on the accuracy of an orbit. The number and spacing of intermediate observations has a lesser effect. Short arcs A very short arc leaves a high uncertainty parameter. The object might be in one of many different orbits, at many distances from Earth. In some cases, the initial arc was too short to determine if the object was in orbit around the Earth, or orbiting out in the asteroid belt. With a 1-day observation arc, was thought to be a trans-Neptunian dwarf planet, but is now known to be a 1 km main-belt asteroid. With an observation arc of 3 days, was thought to be a Mars-crossing asteroid that could be a threat to Earth, but was later ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precovery
In astronomy, precovery (short for pre-discovery recovery) is the process of finding the image of an object in images or photographic plates predating its discovery, typically for the purpose of calculating a more accurate orbit. This happens most often with minor planets, but sometimes a comet, a dwarf planet, a natural satellite, or a star is found in old archived images; even exoplanet precovery observations have been obtained. "Precovery" refers to a pre-discovery image; "recovery" refers to imaging of a body which was lost to our view (as behind the Sun), but is now visible again ''(also see lost minor planet and lost comet)''. Orbit determination requires measuring an object's position on multiple occasions. The longer the interval between observations, the more accurately the orbit can be calculated; however, for a newly discovered object, only a few days' or weeks' worth of measured positions may be available, sufficient only for a preliminary (imprecise) orbit calculatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecliptic
The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic against the background of stars. The ecliptic is an important reference plane and is the basis of the ecliptic coordinate system. Sun's apparent motion The ecliptic is the apparent path of the Sun throughout the course of a year. Because Earth takes one year to orbit the Sun, the apparent position of the Sun takes one year to make a complete circuit of the ecliptic. With slightly more than 365 days in one year, the Sun moves a little less than 1° eastward every day. This small difference in the Sun's position against the stars causes any particular spot on Earth's surface to catch up with (and stand directly north or south of) the Sun about four minutes later each day than it would if Earth did not orbit; a day on Earth is therefore 24 hours ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Earth directly above the Equator, the plane of the satellite's orbit is the same as the Earth's equatorial plane, and the satellite's orbital inclination is 0°. The general case for a circular orbit is that it is tilted, spending half an orbit over the northern hemisphere and half over the southern. If the orbit swung between 20° north latitude and 20° south latitude, then its orbital inclination would be 20°. Orbits The inclination is one of the six orbital elements describing the shape and orientation of a celestial orbit. It is the angle between the orbital plane and the plane of reference, normally stated in degrees. For a satellite orbiting a planet, the plane of reference is usually the plane containing the planet's equator. For pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
