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1566 Icarus
1566 Icarus ( ; ''provisional designation'': ) is a large near-Earth object of the Apollo group and the lowest numbered potentially hazardous asteroid. It has is an extremely eccentric orbit (0.83) and measures approximately in diameter. In 1968, it became the first asteroid ever observed by radar. Its orbit brings it closer to the Sun than Mercury and further out than the orbit of Mars, which also makes it a Mercury-, Venus-, and Mars-crossing asteroid. This stony asteroid and relatively fast rotator with a period of 2.27 hours was discovered on 27 June 1949, by German astronomer Walter Baade at the Palomar Observatory in California. It was named after the mythological Icarus. Orbit and classification Icarus orbits the Sun at a distance of 0.19–1.97 AU once every 13 months (409 days; semi-major axis of 1.08 AU). Its orbit has an eccentricity of 0.83 and an inclination of 23 ° with respect to the ecliptic. The body's observation arc begins with its official ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Icarus Symbol (fixed Width)
In Greek mythology, Icarus (; grc, Ἴκαρος, Íkaros, ) was the son of the master craftsman Daedalus, the architect of the labyrinth of Crete. After Theseus, king of Athens and enemy of Minos, escaped from the labyrinth, King Minos suspected that Icarus and Daedalus had revealed the labyrinth's secrets and imprisoned them--either in a large tower overlooking the ocean or the labyrinth itself, depending upon the account. Icarus and Daedalus escaped using wings Daedalus constructed from feathers, threads from blankets, clothes, and beeswax. Daedalus warned Icarus first of complacency and then of hubris, instructing him to fly neither too low nor too high, lest the sea's dampness clog his wings or the sun's heat melt them. Icarus ignored Daedalus’ instructions not to fly too close to the sun, causing the beeswax in his wings to melt. Icarus fell from the sky, plunged into the sea, and drowned. The myth gave rise to the idiom, " fly too close to the sun". In some versions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Q-type Asteroid
Q-type asteroids are relatively uncommon inner-belt asteroids with a strong, broad 1 micrometre olivine and pyroxene feature, and a spectral slope that indicates the presence of metal. There are absorption features shortwards and longwards of 0.7 μm, and the spectrum is generally intermediate between the V and S-type. Q-type asteroids are spectrally more similar to ordinary chondrite meteorites (types H, L, LL) than any other asteroid type. This has led scientists to speculate that they are abundant, but only about 20 of this type has been characterized. Examples of Q-type asteroids are: 1862 Apollo, 2102 Tantalus, 3753 Cruithne, 6489 Golevka, and 9969 Braille. See also *Asteroid spectral types 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 ... References A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1566 Icarus Orbit
__NOTOC__ Year 1566 ( MDLXVI) was a common year starting on Tuesday (link will display the full calendar) of the Julian calendar. Events January–June * January 7 – Pope Pius V succeeds Pope Pius IV, as the 225th pope. * February 24 – In one of the first gun assassinations in Japanese (if not world) history, Mimura Iechika is shot dead by two brothers (Endo Matajiro and Yoshijiro), sent by his rival Ukita Naoie. * March 28 – The foundation stone of Valletta, which will become Malta's capital city, is laid by Jean Parisot de Valette, Grand Master of the Sovereign Military Order of Malta. * April 5 – The Compromise of Nobles is presented to Margaret of Parma, Governor of the Habsburg Netherlands, but it succeeds only in delaying the beginning of the Eighty Years' War in the Netherlands. July–December * August 6 – The siege of Szigetvár is begun by Suleiman the Magnificent, Sultan of the Ottoman Empire. This is the Ottom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotation Period
The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) may refer to its sidereal rotation period, i.e. the time that the object takes to complete a single revolution around its axis of rotation relative to the background stars, measured in sidereal time. The other type of commonly used rotation period is the object's synodic rotation period (or ''solar day''), measured in solar time, which may differ by a fraction of a rotation or more than one rotation to accommodate the portion of the object's orbital period 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 gas giants, 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 gas giant (such as Jupiter, Saturn, Uranus, Neptune) is its internal rotation period, as d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Fast Rotators (minor Planets)
This is a list of fast rotators—"minor planets" (which includes asteroids) that have an exceptionally short rotation period, also called "rotation rate" or "spin rate". In some cases the rotation period is not constant because the object tumbles (see List of tumblers). In this list the periods are sourced from the ''Light Curve Data Base'' (LCDB), and are given in both seconds and hours. Most minor planets have rotation periods between 2 and 20 hours. , a group of 887 bodies – most of them are stony near-Earth asteroids with small diameters of barely 1 kilometre – have an estimated period of less than 2.2 hours. According to the Minor Planet Center, most small bodies are thought to be rubble piles – conglomerations of smaller pieces, loosely coalesced under the influence of gravity. Bodies with a period below 2.2 hours – known as the "cohesionless spin-barrier" – cannot be merely held together by self-gravity, but must be formed of a contiguous solid, as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars-crossing Asteroid
A Mars-crossing asteroid (MCA, also Mars-crosser, MC) is an asteroid whose orbit crosses that of Mars. Some Mars-crossers Minor planet designation, numbered below 100000 are listed here. They include the two numbered Mars trojans 5261 Eureka and . Many databases, for instance the JPL Small-Body Database (JPL SBDB), only list asteroids with a perihelion greater than 1.3 Astronomical Unit, AU as Mars-crossers. An asteroid with a perihelion less than this is classed as a near-Earth object even though it is crossing the orbit of Mars as well as crossing (or coming near to) that of Earth. Nevertheless, these objects are listed on this page. A grazer is an object with a perihelion below the aphelion of Mars (1.67 AU) but above the Martian perihelion (1.38 AU). The JPL SBDB lists 13,500 Mars-crossing asteroids. Only 18 MCAs are brighter than Absolute magnitude#Solar System bodies (H), absolute magnitude (H) 12.5, which typically makes these asteroids with H<12.5 more than 13 km in d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbit Of Mars
Mars has an orbit with a semimajor axis of 1.524 astronomical units (228 million km), and an eccentricity of 0.0934.Jean Meeus, ''Astronomical Formulæ for Calculators''. (Richmond, VA: Willmann-Bell, 1988) 99. Elements by F. E. Ross The planet orbits the Sun in 687 days and travels 9.55 AU in doing so,Jean Meeus, ''Astronomical Algorithms'' (Richmond, VA: Willmann-Bell, 1998) 238. The formula by Ramanujan is accurate enough. making the average orbital speed 24 km/s. The eccentricity is greater than that of every other planet except Mercury, and this causes a large difference between the aphelion and perihelion distances—they are 1.6660 and 1.3814 AU. Changes in the orbit Mars is in the midst of a long-term increase in eccentricity. It reached a minimum of 0.079 about 19 millennia ago, and will peak at about 0.105 after about 24 millennia from now (and with perihelion distances a mere 1.3621 astronomical units). The orbit is at times near circular: it was 0.00 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury (planet)
Mercury is the smallest planet in the Solar System and the closest to the Sun. Its orbit around the Sun takes 87.97 Earth days, the shortest of all the Sun's planets. It is named after the Roman god ' ( Mercury), god of commerce, messenger of the gods, and mediator between gods and mortals, corresponding to the Greek god Hermes (). Like Venus, Mercury orbits the Sun within Earth's orbit as an inferior planet, and its apparent distance from the Sun as viewed from Earth never exceeds 28°. This proximity to the Sun means the planet can only be seen near the western horizon after sunset or the eastern horizon before sunrise, usually in twilight. At this time, it may appear as a bright star-like object, but is more difficult to observe than Venus. From Earth, the planet telescopically displays the complete range of phases, similar to Venus and the Moon, which recurs over its synodic period of approximately 116 days. The synodic proximity of Mercury to Earth makes Mercury most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar Astronomy
Radar astronomy is a technique of observing nearby astronomical objects by reflecting radio waves or microwaves off target objects and analyzing their reflections. Radar astronomy differs from ''radio astronomy'' in that the latter is a passive observation (i.e., receiving only) and the former an active one (transmitting and receiving). Radar systems have been conducted for six decades applied to a wide range of Solar System studies. The radar transmission may either be pulsed or continuous. The strength of the radar return signal is proportional to the inverse fourth-power of the distance. Upgraded facilities, increased transceiver power, and improved apparatus have increased observational opportunities. Radar techniques provide information unavailable by other means, such as testing general relativity by observing Mercury and providing a refined value for the astronomical unit. Radar images provide information about the shapes and surface properties of solid bodies, which ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. Of the roughly one million known asteroids the greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4 AU from the Sun, in the main asteroid belt. Asteroids are generally classified to be of three types: C-type, M-type, and S-type. These were named after and are generally identified with carbonaceous, metallic, and silicaceous compositions, respectively. The size of asteroids varies greatly; the largest, Ceres, is almost across and qualifies as a dwarf planet. The total mass of all the asteroids combined is only 3% that of Earth's Moon. The majority of main belt asteroids follow slightly elliptical, stable orbits, revolving in the same direction as the Earth and taking from three to six years to comple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eccentric 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: ''e'' = 0 * elliptic orbit: 0 < ''e'' < 1 * [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potentially Hazardous Asteroid
A potentially hazardous object (PHO) is a near-Earth object – either an asteroid or a comet – with an orbit that can make close approaches to the Earth and is large enough to cause significant regional damage in the event of impact. They are defined as having a minimum orbit intersection distance with Earth of less than and an absolute magnitude of 22 or brighter. More than 99% of the known potentially hazardous objects are not an impact threat over the next 100 years. , only 17 potentially hazardous objects are listed on the Sentry Risk Table as objects that are known not to be a threat over the next hundred years are excluded. Over hundreds if not thousands of years, "potentially hazardous" asteroids have the potential for their orbits to evolve to live up to their namesake. Most of these objects are potentially hazardous asteroids (PHAs), and a few are comets. there are 2,304 known PHAs (about 8% of the total near-Earth population), of which 153 are estimated to be large ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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