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1996 PW
is an exceptionally eccentric trans-Neptunian object and a damocloid on an orbit typical of long-period comets but one that showed no sign of cometary activity around the time it was discovered. The unusual object measures approximately in diameter and has a rotation period of 35.4 hours and likely an elongated shape. Description orbits the Sun at a distance of 2.5–504 AU once every 4,033 years (semi-major axis of 253 AU). Its orbit has an eccentricity of 0.99 and an inclination of 30 ° with respect to the ecliptic. Simulations indicate that it has most likely come from the Oort cloud, with a roughly equal probability of being an extinct comet and a rocky body that was originally scattered into the Oort cloud. The discovery of prompted theoretical research that suggests that roughly 1 to 2 percent of the Oort cloud objects are rocky. was first observed on 9 August 1996 by the Near-Earth Asteroid Tracking (NEAT) automated search camera on Haleakala Observ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Near-Earth Asteroid Tracking
Near-Earth Asteroid Tracking (NEAT) was a program run by NASA and the Jet Propulsion Laboratory, surveying the sky for near-Earth objects. NEAT was conducted from December 1995 until April 2007, at GEODSS on Hawaii (Haleakala-NEAT; 566), as well as at Palomar Observatory in California (Palomar-NEAT; 644). With the discovery of more than 40 thousand minor planets, NEAT has been one of the most successful programs in this field, comparable to the Catalina Sky Survey, LONEOS and Mount Lemmon Survey. NEAT was the successor to the Palomar Planet-Crossing Asteroid Survey (PCAS). History The original principal investigator was Eleanor F. Helin, with co-investigators Steven H. Pravdo and David L. Rabinowitz. NEAT had a cooperative agreement with the U.S. Air Force to use a GEODSS telescope located on Haleakala, Maui, Hawaii. GEODSS stands for Ground-based Electro-Optical Deep Space Surveillance and these wide field Air Force telescopes were designed to optically observ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-period Comet
A comet is an icy, small Solar System body 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. These phenomena are due to the effects of solar radiation and the outstreaming solar wind plasma acting upon the nucleus of the comet. Comet nuclei range from a few hundred meters to tens of kilometers across and are composed of loose collections of ice, dust, and small rocky particles. The coma may be up to 15 times Earth's diameter, while the tail may stretch beyond one astronomical unit. If sufficiently close and bright, a comet may be seen from Earth without the aid of a telescope and can subtend an arc of up to 30° (60 Moons) across the sky. Comets have been observed and recorded since ancient times by many cultures and religions. Comets usually have highly eccentric el ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lowell Observatory
Lowell Observatory is an astronomical observatory in Flagstaff, Arizona, United States. Lowell Observatory was established in 1894, placing it among the oldest observatories in the United States, and was designated a National Historic Landmark in 1965. and In 2011, the Observatory was named one of "The World's 100 Most Important Places" by Time Magazine. It was at the Lowell Observatory that the dwarf planet Pluto was discovered in 1930 by Clyde Tombaugh. The observatory was founded by astronomer Percival Lowell of Boston's Lowell family and is overseen by a sole trustee, a position historically handed down through the family. The first trustee was Lowell's third cousin Guy Lowell (1916–1927). Percival's nephew Roger Putnam served from 1927 to 1967, followed by Roger's son Michael (1967–1987), Michael's brother William Lowell Putnam III (1987–2013), and current trustee W. Lowell Putnam. Multiple astronauts attended the Lowell Observatory in 1963 while the moon was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Solar System Objects By Greatest Aphelion
This is a list of Solar System objects by greatest aphelion or the greatest distance from the Sun that the orbit could take it if the Sun and object were the only objects in the universe. It is implied that the object is orbiting the Sun Two-body problem, in a two-body solution without the influence of the planets, passing stars, or the galaxy. The aphelion can change significantly due to the gravitational influence of planets and other stars. Most of these objects are comets on a calculated path and may not be directly observable. For instance, comet Comet Hale–Bopp, Hale-Bopp was last seen in 2013 at apparent magnitude, magnitude 24 and continues to fade, making it invisible to all but the most powerful telescopes. The maximum extent of the region in which the Sun's gravitational field is dominant, the Hill sphere, may extend to as calculated in the 1960s. But any comet currently more than about from the Sun can be considered lost to the interstellar medium. The nearest kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinct Comets
An extinct comet is a comet that has expelled most of its Volatile (astrogeology), volatile ice and has little left to form a Comet tail, tail and coma (cometary), 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. When volatile materials such as nitrogen, water, carbon dioxide, ammonia, hydrogen and methane in the comet nucleus have evaporated away, all that remains is an inert rock or rubble pile. A comet may go through a transition phase as it comes close to extinction. Nature of extinct comets Extinct comets are those that have expelled most of their volatile ice and have little left to form a tail or coma. Over time, most of the volatile material contained in a comet nucleus evaporates away, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LCDB Quality Code
In astronomy, a light curve is a graph of the 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, cataclysmic variable star, supernova, 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 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnitude (astronomy)
In astronomy, magnitude is a measure of the brightness of an astronomical object, object, usually in a defined passband. An imprecise but systematic determination of the magnitude of objects was introduced in ancient times by Hipparchus. Magnitude values do not have a unit. 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 definitions of magnitude: apparent magnitude and absolute magnitude. The ''apparent'' magnitude () is the brightness of an object and depends on an object's intrinsic luminosity, its Cosmic distance ladder, distance, and the Extinction (astronomy), extinction reducing its brightness. The ''absolute'' magnitude () describes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinct Comet
An 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. When volatile materials such as nitrogen, water, carbon dioxide, ammonia, hydrogen and methane in the comet nucleus have evaporated away, all that remains is an inert rock or rubble pile. A comet may go through a transition phase as it comes close to extinction. Nature of extinct comets Extinct comets are those that have expelled most of their volatile ice and have little left to form a tail or coma. Over time, most of the volatile material contained in a comet nucleus evaporates away, and the comet becomes a small, dark, inert lump of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oort Cloud
The Oort cloud (pronounced or ), sometimes called the Öpik–Oort cloud, is scientific theory, theorized to be a cloud of billions of Volatile (astrogeology), icy planetesimals surrounding the Sun at distances ranging from 2,000 to 200,000 Astronomical unit, AU (0.03 to 3.2 light-years). The cloud was proposed in 1950 by the Dutch astronomer Jan Oort, in whose honor the idea was named. Oort proposed that the bodies in this cloud replenish and keep constant the number of Comet, long-period comets entering the inner Solar System—where they are eventually consumed and destroyed during close approaches to the Sun. The cloud is thought to encompass two regions: a circumstellar disc, disc-shaped inner Oort cloud aligned with the Ecliptic, solar ecliptic (also called its Hills cloud) and a circumstellar envelope, spherical outer Oort cloud enclosing the entire Solar System. Both regions lie well beyond the heliosphere and are in Outer space#Interstellar space, interstellar space. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecliptic
The ecliptic or ecliptic plane is the orbital plane of Earth's orbit, Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making. 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 fixed stars, background of stars – specifically the Zodiac constellations. The planets of the Solar System can also be seen along the ecliptic, because their orbital planes are very close to Earth's. The Moon's orbital plane is also similar to Earth's; the ecliptic is so named because the ancients noted that eclipses only occur when the Moon is crossing it. The ecliptic is an important Plane of reference, reference plane and is the basis of the ecliptic coordinate system. Ancient scientists were able to calculate Earth's axial tilt by comparing the ecliptic plane to that of ... [...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] |
Orbital Eccentricity
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
