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Pallas Family
The Pallas family (''adj. Palladian''; ) is a small asteroid family of B-type asteroids at very high Orbital inclination, inclinations in the intermediate asteroid belt. The family was identified by Kiyotsugu Hirayama in 1928. The namesake of the family is 2 Pallas, an extremely large asteroid with a mean diameter of about 512 km. The remaining Palladian asteroids are far smaller; the largest is 5222 Ioffe with an estimated diameter of 22 km. This, along with the preponderance of the otherwise rare B spectral type among its members, indicates that this is likely a ''cratering'' family composed of ejecta from impacts on Pallas. Another suspected Palladian is 3200 Phaethon, the parent body of the Geminids, Geminid meteor shower. From the diagram, their proper orbital elements lie in the approximate ranges At the present epoch (astronomy), epoch, the range of osculating orbit, osculating orbital elements of the members (by comparison to the MPCORB databas is about ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family Identification Number
An asteroid family is a population of asteroids that share similar proper orbital elements, such as semimajor axis, eccentricity (orbit), eccentricity, and orbital inclination. The members of the families are thought to be Collisional family, fragments of past asteroid collisions. An asteroid family is a more specific term than list of minor-planet groups, asteroid group whose members, while sharing some broad orbital characteristics, may be otherwise unrelated to each other. General properties Large prominent families contain several hundred recognized asteroids (and many more smaller objects which may be either not-yet-analyzed, or not-yet-discovered). Small, compact families may have only about ten identified members. About 33% to 35% of asteroids in the main belt are family members. There are about 20 to 30 reliably recognized families, with several tens of less certain groupings. Most asteroid families are found in the main belt, main asteroid belt, although several famil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pallas Family
The Pallas family (''adj. Palladian''; ) is a small asteroid family of B-type asteroids at very high Orbital inclination, inclinations in the intermediate asteroid belt. The family was identified by Kiyotsugu Hirayama in 1928. The namesake of the family is 2 Pallas, an extremely large asteroid with a mean diameter of about 512 km. The remaining Palladian asteroids are far smaller; the largest is 5222 Ioffe with an estimated diameter of 22 km. This, along with the preponderance of the otherwise rare B spectral type among its members, indicates that this is likely a ''cratering'' family composed of ejecta from impacts on Pallas. Another suspected Palladian is 3200 Phaethon, the parent body of the Geminids, Geminid meteor shower. From the diagram, their proper orbital elements lie in the approximate ranges At the present epoch (astronomy), epoch, the range of osculating orbit, osculating orbital elements of the members (by comparison to the MPCORB databas is about ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Elements
Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit. There are many different ways to mathematically describe the same orbit, but certain schemes are commonly used in astronomy and orbital mechanics. A real orbit and its elements change over time due to gravitational Perturbation (astronomy), perturbations by other objects and the effects of general relativity. A Kepler orbit is an idealized, mathematical approximation of the orbit at a particular time. When viewed from an inertial frame, two orbiting bodies trace out distinct trajectories. Each of these trajectories has its Focus (geometry), focus at the common center of mass. When viewed from a non-inertial frame centered on one of the bodies, only the trajectory of the opposite body is apparent; Keplerian elements describe these non-inertial trajectories. An orbit has two sets of Keplerian elements depe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osculating Orbit
In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space at a given moment in time is the gravitational Kepler orbit (i.e. an elliptic or other conic one) that it would have around its central body if perturbations were absent. That is, it is the orbit that coincides with the current orbital state vectors (position and velocity). Etymology The word '' osculate'' is Latin for "kiss". In mathematics, two curves osculate when they just touch, without (necessarily) crossing, at a point, where both have the same position and slope, i.e. the two curves "kiss". Kepler elements An osculating orbit and the object's position upon it can be fully described by the six standard Kepler orbital elements (osculating elements), which are easy to calculate as long as one knows the object's position and velocity relative to the central body. The osculating elements would remain constant in the absence of perturbations. Real astronomical orbits experience pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epoch (astronomy)
In astronomy, an epoch or reference epoch is a instant, moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a Astronomical object, celestial body, as they are subject to Perturbation (astronomy), perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or Perihelion and aphelion, aphelion of its orbit, or the size of the major axis of its orbit. The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical Unit
The astronomical unit (symbol: au or AU) is a unit of length defined to be exactly equal to . Historically, the astronomical unit was conceived as the average Earth-Sun distance (the average of Earth's aphelion and perihelion), before its modern redefinition in 2012. The astronomical unit is used primarily for measuring distances within the Solar System or around other stars. It is also a fundamental component in the definition of another unit of astronomical length, the parsec. One au is approximately equivalent to 499 light-seconds. History of symbol usage A variety of unit symbols and abbreviations have been in use for the astronomical unit. In a 1976 resolution, the International Astronomical Union (IAU) had used the symbol ''A'' to denote a length equal to the astronomical unit. In the astronomical literature, the symbol AU is common. In 2006, the International Bureau of Weights and Measures (BIPM) had recommended ua as the symbol for the unit, from the French ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eccentricity (orbit)
In astrodynamics, the orbital eccentricity of an astronomical object is a dimensionless parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is a circular orbit, values between 0 and 1 form an elliptic orbit, 1 is a parabolic escape orbit (or capture orbit), and greater than 1 is a hyperbola. The term derives its name from the parameters of conic sections, as every Kepler orbit is a conic section. It is normally used for the isolated two-body problem, but extensions exist for objects following a rosette orbit through the Galaxy. Definition In a two-body problem with inverse-square-law force, every orbit is a Kepler orbit. The eccentricity of this Kepler orbit is a non-negative number that defines its shape. The eccentricity may take the following values: * Circular orbit: * Elliptic orbit: * Parabolic trajectory: * Hyperbolic trajectory: The eccentricity is given by e = \sqrt where is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semi-major Axis
In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the longest semidiameter or one half of the major axis, and thus runs from the centre, through a focus, and to the perimeter. The semi-minor axis (minor semiaxis) of an ellipse or hyperbola is a line segment that is at right angles with the semi-major axis and has one end at the center of the conic section. For the special case of a circle, the lengths of the semi-axes are both equal to the radius of the circle. The length of the semi-major axis of an ellipse is related to the semi-minor axis's length through the eccentricity and the semi-latus rectum \ell, as follows: The semi-major axis of a hyperbola is, depending on the convention, plus or minus one half of the distance between the two branches. Thus it is the distance from the ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proper Orbital Elements
__NOTOC__ The proper orbital elements or proper elements of an orbit are constants of motion of an object in space that remain practically unchanged over an astronomically long timescale. The term is usually used to describe the three quantities: *''proper semimajor axis'' (''ap''), *''proper eccentricity'' (''ep''), and *''proper inclination'' (''ip''). The proper elements can be contrasted with the osculating Keplerian orbital elements observed at a particular time or epoch, such as the semi-major axis, eccentricity, and inclination. Those osculating elements change in a quasi-periodic and (in principle) predictable manner due to such effects as perturbations from planets or other bodies, and precession (e.g. perihelion precession). In the Solar System, such changes usually occur on timescales of thousands of years, while proper elements are meant to be practically constant over at least tens of millions of years. For most bodies, the osculating elements are relatively clos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geminids
The Geminids are a prolific meteor shower with 3200 Phaethon (which is thought to be an Apollo asteroid with a " rock comet" orbit.) being the parent body. Because of this, it would make this shower, along with the Quadrantids, the only major meteor showers not originating from a comet. The meteors from this shower are slow, they can be seen in December and usually peak around December 4–16, with the date of highest intensity being the morning of December 14. Current showers produce up to 120–160 meteors per hour under optimal conditions, peaking around 2:00 or 3:00. Geminids were first observed in 1862, much later than other showers such as the Perseids (36 AD) and Leonids (902 AD). Based on data from the Parker Solar Probe, a 2023 study suggested that the Geminids may have been formed by the catastrophic breakup of a comet that formed asteroids 2005 UD and 1999 YC in addition to Phaethon. Background The Geminid meteor shower is unique among celestial events as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FIN Tbl
An asteroid family is a population of asteroids that share similar proper orbital elements, such as semimajor axis, eccentricity, and orbital inclination. The members of the families are thought to be fragments of past asteroid collisions. An asteroid family is a more specific term than asteroid group whose members, while sharing some broad orbital characteristics, may be otherwise unrelated to each other. General properties Large prominent families contain several hundred recognized asteroids (and many more smaller objects which may be either not-yet-analyzed, or not-yet-discovered). Small, compact families may have only about ten identified members. About 33% to 35% of asteroids in the main belt are family members. There are about 20 to 30 reliably recognized families, with several tens of less certain groupings. Most asteroid families are found in the main asteroid belt, although several family-like groups such as the Pallas family, Hungaria family, and the Phocaea fam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
