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99 Dike
Dike ( minor planet designation: 99 Dike) is a quite large and dark main-belt asteroid. Dike was discovered by Alphonse Borrelly on May 28, 1868. It was his first asteroid discovery. This object is named after Dike, the Greek goddess of moral justice. Among the first hundred numbered minor planets, 99 Dike was considered anomalously faint for over a century. However, this was later found to be untrue. This asteroid is orbiting the Sun with a period of 4.35 years and an eccentricity of 0.19. Its orbital plane is inclined by 13.8° to the plane of the ecliptic. The body spans a diameter of 69 km and it is classified as a C-type asteroid, which indicates it has a dark, carbonaceous surface. Based upon a light curve that was generated from photometric observations of this asteroid at Pulkovo Observatory, it has a rotation period of 18.127 ± 0.002 hours and varies in brightness by 0.22 ± 0.02 in magnitude. However, according to Shrindan E. (2009) the rotation period is r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alphonse Borrelly
Alphonse Louis Nicolas Borrelly (December 8, 1842 – February 28, 1926) was a French astronomer. He joined the Marseille Observatory in 1864. In the course of his career, he discovered a number of asteroids and comets, including the periodic comet 19P/Borrelly. The French Academy of Sciences awarded him the Prix Valz for 1903 and the Prix Lalande for 1909. The asteroid 1539 Borrelly was named in his honor. In 1913, he received the Prix Jules Janssen, the highest award of the Société astronomique de France, the French astronomical society. Comets discovered or co-discovered The following is an incomplete list of comets discovered or co-discovered by Borrelly: * C/1873 Q1 (Borrelly) * C/1877 C1 (Borrelly) * C/1877 G2 (Swift-Borrelly-Block) * C/1889 X1 (Borrelly) * 19P/Borrelly Comet Borrelly or Borrelly's Comet (official designation: 19P/Borrelly) is a periodic comet, which was visited by the spacecraft Deep Space 1 in 2001. The comet last came to perihelion (closest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dike (goddess)
In Greek mythology, Dike or Dice ( or ; Greek: ) is the goddess of justice and the spirit of moral order and fair judgement as a transcendent universal ideal or based on immemorial custom, in the sense of socially enforced norms and conventional rules. According to Hesiod (''Theogony'', l. 901), she was fathered by Zeus upon his second consort, Themis. She and her mother are both personifications of justice. She is depicted as a young, slender woman carrying a balance scale and wearing a laurel wreath. The constellation Libra (the Scales) was anciently thought to represent her distinctive symbol. She is often associated with Astraea, the goddess of innocence and purity. ''Astraea'' is also one of her epithets, referring to her appearance in the nearby constellation Virgo which is said to represent Astraea. This reflects her symbolic association with Astraea, who, too, has a similar iconography. Depiction The sculptures of the Temple of Zeus at Olympia have as their unifying i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C-type Asteroids (Tholen)
C-type (carbonaceous) asteroids are the most common variety, forming around 75% of known asteroids. They are volatile-rich and distinguished by a very low albedo because their composition includes a large amount of carbon, in addition to rocks and minerals. Their density averages at about . They occur most frequently at the outer edge of the asteroid belt, 3.5 astronomical units (AU) from the Sun, where 80% of the asteroids are of this type, whereas only 40% of asteroids at 2 AU from the Sun are C-type. The proportion of C-types may actually be greater than this, because C-types are much darker (and therefore Sampling bias, less detectable) than most other asteroid types except for D-type asteroid, D-types and others that are mostly at the extreme outer edge of the asteroid belt. Characteristics Asteroids of this class have spectrum, spectra very similar to those of carbonaceous chondrite meteorites (types CI and CM). The latter are very close in chemical composition to the Sun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Juno Clump
The Juno clump is a probable main-belt asteroid family that share similar orbital elements to 3 Juno. 3 Juno is a large asteroid with a mean diameter of about 235 km, but the remaining bodies are all small. , the brightest of those clearly in the visible clump would have a diameter of about 6 km, given the same albedo as 3 Juno. This indicates that it is probably a so-called cratering family composed of ejecta from impacts on 3 Juno. The HCM analysis by (Zappalà 1995) determined several likely core members, whose proper elements lie in the approximate ranges At the present epoch, the range of osculating 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 ... of these core members is References * Zappalà, Vincenzo; Bendjoya, Philippe; Cellino, Alberto ... [...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] |
Pulkovo Observatory
The Pulkovo Astronomical Observatory (russian: Пулковская астрономическая обсерватория, Pulkovskaya astronomicheskaya observatoriya), officially named the Central Astronomical Observatory of the Russian Academy of Sciences at Pulkovo, is the principal astronomical observatory of the Russian Academy of Sciences. It is located 19 km south of Saint Petersburg on Pulkovo Heights above sea level. It is part of the UNESCO World Heritage Site Historic Centre of Saint Petersburg and Related Groups of Monuments. It was formerly known as the Imperial Observatory at Pulkowo. Early years The observatory was opened in 1839. Originally, it was a brainchild of the German/Russian astronomer Friedrich Georg Wilhelm von Struve, who would become its first director (in 1861, his son Otto Wilhelm von Struve succeeded him). The architect was Alexander Bryullov. The observatory was equipped with state-of-the-art devices, one of them being the a aperture ref ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photometry (astronomy)
Photometry, from Greek '' photo-'' ("light") and '' -metry'' ("measure"), is a technique used in astronomy that is concerned with measuring the flux or intensity of light radiated by astronomical objects. This light is measured through a telescope using a photometer, often made using electronic devices such as a CCD photometer or a photoelectric photometer that converts light into an electric current by the photoelectric effect. When calibrated against standard stars (or other light sources) of known intensity and colour, photometers can measure the brightness or apparent magnitude of celestial objects. The methods used to perform photometry depend on the wavelength region under study. At its most basic, photometry is conducted by gathering light and passing it through specialized photometric optical bandpass filters, and then capturing and recording the light energy with a photosensitive instrument. Standard sets of passbands (called a photometric system) are defined to allow a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Curve
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 s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbonaceous
Carbon () is a chemical element with the chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—its atom making four electrons available to form covalent bond, covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three Isotopes of carbon, isotopes occur naturally, Carbon-12, C and Carbon-13, C being stable, while Carbon-14, C is a radionuclide, decaying with a half-life of about 5,730 years. Carbon is one of the Timeline of chemical element discoveries#Ancient discoveries, few elements known since antiquity. Carbon is the 15th Abundance of elements in Earth's crust, most abundant element in the Earth's crust, and the Abundance of the chemical elements, fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. Carbon's abundance, its unique diversity of organic compounds, and its unusual ability to form polymers at the tempera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plane Of The 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] |
Orbital Plane
The orbital plane of a revolving body is the geometric plane in which its orbit lies. Three non-collinear points in space suffice to determine an orbital plane. A common example would be the positions of the centers of a massive body (host) and of an orbiting celestial body at two different times/points of its orbit. The orbital plane is defined in relation to a reference plane by two parameters: inclination (''i'') and longitude of the ascending node (Ω). By definition, the reference plane for the Solar System is usually considered to be Earth's orbital plane, which defines the ecliptic, the circular path on the celestial sphere that the Sun appears to follow over the course of a year. In other cases, for instance a moon or artificial satellite orbiting another planet, it is convenient to define the inclination of the Moon's orbit as the angle between its orbital plane and the planet's equatorial plane. Artificial satellites around the Earth For launch vehicles and ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
