This article is about 20000 Varuna, a minor planet. For other uses of the word, see Varuna (disambiguation)

20000 Varuna

Artist's conception of Varuna
Discovery
Discovered by	R. McMillan (Spacewatch)
Discovery date	28 November 2000
Designations
MPC designation	20000 Varuna
Alternative names	2000 WR106
Minor planet category	TNO (cubewano)
Orbital characteristics
Epoch 14 July 2004 (JD 2453200. Robert S McMillan is an Astronomer at the University of Arizona, and heads the Spacewatch project which studies Minor planets He has made Spacewatch is a project at the University of Arizona that specializes in the study of Minor planets including various types of Asteroids and Comets For the town in Argentina, see 28 de Noviembre. Events 2000 ( MM) was a Leap year that started on Saturday of the Common Era, in accordance with the Gregorian calendar. A provisional designation in astronomy is the naming convention applied to Astronomical objects immediately following their discovery A trans-Neptunian object (TNO is any object in the Solar system that Orbits the sun at a greater distance on average than Neptune. In astronomy a classical Kuiper Belt object, also called a cubewano (ˌkjuːbiːˈwɑːnoʊ is a Kuiper belt object that Orbits beyond Neptune In Physics, an orbit is the gravitationally curved path of one object around a point or another body for example the gravitational orbit of a planet around a star In Astronomy, an epoch is a moment in time used as a reference for the Orbital elements of a Celestial body. Events 1223 - Louis VIII becomes King of France upon the death of his father Philip II of France. "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " The Julian date (JD is the interval of time in days and fractions of a day since 4713 B 5)
Aphelion	6781. In Celestial mechanics, an apsis, plural apsides (ˈæpsɨdɪːz is the point of greatest or least distance of the Elliptical orbit of an object from 985 Gm (45. 335 AU)
Perihelion	6120. In Celestial mechanics, an apsis, plural apsides (ˈæpsɨdɪːz is the point of greatest or least distance of the Elliptical orbit of an object from 810 Gm (40. 915 AU)
Semi-major axis	6451. In Geometry, the semi-major axis (also semimajor axis) is used to describe the dimensions of ellipses and hyperbolae 398 Gm (43. For other meanings see Giga (disambiguation Giga- (symbol G is a prefix in the SI system of units denoting 109 The metre or meter is a unit of Length. It is the basic unit of Length in the Metric system and in the International 129 AU)
Eccentricity	0. The astronomical unit ( AU or au or au or sometimes ua) is a unit of Length based on the distance from the Earth to the In Astrodynamics, under standard assumptions, any Orbit must be of Conic section shape 051
Orbital period	103440. The orbital period is the time taken for a given object to make one complete Orbit about another object 6 d (283. A day (symbol d is a unit of Time equivalent to 24 Hours and the duration of a single Rotation of planet Earth with respect to the 20 a)
Average orbital speed	4. A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun The orbital speed of a body generally a Planet, a Natural satellite, an artificial satellite, or a Multiple star, is the speed at which it 53 km/s
Mean anomaly	89. In the study of orbital dynamics the mean anomaly of an orbiting body is the Angle the body would have traveled about the center of the orbit's Auxiliary circle 673°
Inclination	17. Inclination in general is the Angle between a Reference plane and another plane or axis of direction 2°
Longitude of ascending node	97. This article describes the unit of angle For other meanings see Degree. The longitude of the ascending node (☊ or Ω is one of the Orbital elements used to specify the Orbit of an object in space 296°
Argument of perihelion	271. The argument of periapsis (or argument of perifocus) ( ω) is the Orbital element describing the Angle of an Orbiting body's periapsis 631°
Physical characteristics
Dimensions	874 km (avg of thermals)[1]
Mass	~5. The kilometre ( American spelling: kilometer) symbol km is a unit of Length in the Metric system, equal to one thousand Mass is a fundamental concept in Physics, roughly corresponding to the Intuitive idea of how much Matter there is in an object 9×1020 kg
Mean density	0. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 992 g/cm³[2]
Equatorial surface gravity	0. For other uses of the words gram or gramme see Gram (disambiguation. A cubic centimetre or cubic centimeter (symbol cm3 —the abbreviation cc, though widely used is deprecated is a commonly used unit of Volume The surface gravity, g, of an astronomical or other object is the Gravitational acceleration experienced at its surface 15 m/s²
Escape velocity	0. In Physics, escape velocity is the speed where the Kinetic energy of an object is equal to the magnitude of its Gravitational potential energy 39 km/s
Sidereal rotation period	0. The rotation period of an astronomical object is the time it takes to complete one revolution around its Axis of rotation relative to the background stars 13216 d (3. 17 h)
Albedo	0. The hour (symbol h) is a unit of Time. It is not an SI unit but is accepted for use with the SI The albedo of an object is the extent to which it diffusely reflects light from the sun 037-0. 21
Temperature	~43-41 K
Spectral type	(moderately red) B-V=0. Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic 93 V-R=0. 64[3]
Absolute magnitude	3. In Astronomy, absolute magnitude (also known as absolute visual magnitude) is the Apparent magnitude an object would have if it were at a standard 7

20000 Varuna (pronounced /ˈvɑːrənə/, or less anglicized /ˈvʌruːnə/, from Sanskrit वरुण) is a large classical Kuiper Belt object (KBO). Sanskrit (sa संस्कृता वाक् saṃskṛtā vāk, for short sa संस्कृतम् saṃskṛtam) is a historical In astronomy a classical Kuiper Belt object, also called a cubewano (ˌkjuːbiːˈwɑːnoʊ is a Kuiper belt object that Orbits beyond Neptune The Kuiper belt (ˈkaɪpɚ to rhyme with "viper" sometimes called the Edgeworth-Kuiper belt, is a region of the Solar System beyond the planets extending It previously had the provisional designation 2000 WR₁₀₆ and has been precovered in plates dating back to 1953. A provisional designation in astronomy is the naming convention applied to Astronomical objects immediately following their discovery Precovery (prediscovery is a term used in Astronomy that describes the process of finding the Image of an object (usually a Minor planet, but sometimes Under the International Astronomical Union's 2006 draft proposal for the definition of a planet, Varuna would be labelled a dwarf planet if it were proven to be spherical. A dwarf planet, as defined by the International Astronomical Union (IAU is a Celestial body Orbiting the Sun that is massive enough to be rounded "Globose" redirects here See also Globose nucleus. A sphere (from Greek σφαίρα - sphaira, "globe

Name

Varuna is named after the Hindu god Varuna. In Hinduism In Hinduism, the Asura ( Sanskrit: असुर are a group of power-seeking deities sometimes referred to as Demons or sinful In Vedic religion, Varuna or Waruna ( Devanagari:वरुण IAST: varuṇa) is a god of the Sky, of Rain and He is the god of the sky, rain, oceans and rivers, and the celestial ocean. The sky is the part of the Atmosphere or of Outer space visible from the surface of any Astronomical object. Rain is Liquid precipitation. On Earth it is the condensation of atmospheric Water vapor into drops heavy enough to fall often making it to An ocean (from Greek, ''Okeanos'' (Oceanus) is a major body of saline water, and a principal component of the Hydrosphere. "Riverine" redirects here For the use of that term in Maritime geography, see there Several mythologies have the notion of a celestial ocean or river, enveloping the World both above the heavenly sphere and below the Underworld He is also a god of law and the underworld, especially concerned with the souls of the drowned. Law is a system of rules enforced through a set of Institutions used as an instrument to underpin civil obedience politics economics and society In the study of Mythology and Religion, the underworld (gr κάτω κόσμος) is a generic term approximately equivalent to the lay term Afterlife He is sometimes considered analogous to Poseidon. In Greek mythology, Poseidon ( Greek:; Latin: Neptūnus) was the god of the Sea and as "Earth-Shaker"

Size

Varuna compared to Eris, Pluto, (136472) 2005 FY₉, (136108) 2003 EL₆₁, Sedna, Orcus, Quaoar, and Earth.

The size of the large KBOs can be determined by simultaneous observations of thermal emission and reflected sunlight. Unfortunately, thermal measures, intrinsically weak for distant objects are further hampered by the absorption of the Earth atmosphere as only the weak ‘tail’ of the emissions is accessible to Earth-based observations. In addition, the estimates are model-dependent with the unknown parameters (e. g. pole orientation and thermal inertia) to be assumed. Consequently, the estimates of the albedo vary resulting in sometimes substantial differences in the inferred size.

A recent thermal model estimates the size at 936 ⁺²³⁸₋₃₂₄ km. ^[4] This estimate is based on earlier results (900 ⁺¹²⁹₋₁₄₅) ^[5] and (1060 ⁺¹⁸⁰_−-220). ^[6]

Orbit

Orbits of Varuna (blue) and Pluto (red).

Varuna is classified as a classical trans-Neptunian object and follows a near-circular orbit with a semi-major axis of ~43 AU, similar to that of Quaoar but more inclined. In astronomy a classical Kuiper Belt object, also called a cubewano (ˌkjuːbiːˈwɑːnoʊ is a Kuiper belt object that Orbits beyond Neptune A trans-Neptunian object (TNO is any object in the Solar system that Orbits the sun at a greater distance on average than Neptune. In Geometry, the semi-major axis (also semimajor axis) is used to describe the dimensions of ellipses and hyperbolae The astronomical unit ( AU or au or au or sometimes ua) is a unit of Length based on the distance from the Earth to the Inclination in general is the Angle between a Reference plane and another plane or axis of direction Its orbital period is similar to Quaoar at 283 Earth years. The graph shows the polar view (top; Varuna’s orbit in blue, Pluto’s in red, Neptune in grey). Neptune ( English|AmE] ] is the eighth and farthest Planet from the Sun in the Solar System. The spheres illustrate the current (April 2006) positions, relative sizes and colours. The perihelia (q), aphelia (Q) and the dates of passage are also marked. In Celestial mechanics, an apsis, plural apsides (ˈæpsɨdɪːz is the point of greatest or least distance of the Elliptical orbit of an object from In Celestial mechanics, an apsis, plural apsides (ˈæpsɨdɪːz is the point of greatest or least distance of the Elliptical orbit of an object from Interestingly, the orbits of Varuna and Pluto have similar inclination and are similarly oriented (the nodes of both orbits are quite close). An orbital node is one of the two points where an Orbit crosses a Plane of reference which it is inclined to

At 43 AU and on a near-circular orbit, unlike Pluto which is in 2:3 orbital resonance with Neptune, Varuna is free from any significant perturbation from Neptune. In Celestial mechanics, an orbital resonance occurs when two Orbiting bodies exert a regular periodic gravitational influence on each other usually due to their The ecliptic view illustrates the comparison of Varuna's near-circular orbit with that of Pluto (highly eccentric, e=0. 25), both similarly inclined.

Physical characteristics

Varuna has a rotational period of approximately 3. 17 hours (or 6. 34 hours, depending on whether the light curve is single or double-peaked). In Astronomy, a light curve is a graph of light intensity of a Celestial object or region as a function of time Given the rapid rotation, rare for objects so large, Varuna is thought to be an elongated spheroid (ratio of axis 2:3), with a mean density around 1g/cm³ (roughly the density of water ice). ^[7] Examination of Varuna's light curve has found that the best-fit model for Varuna is a triaxial ellipsoid with the axes a,b,c in relations: b/a = 0. In Astronomy, a light curve is a graph of light intensity of a Celestial object or region as a function of time An ellipsoid is a type of quadric surface that is a higher dimensional analogue of an Ellipse. 63 − 0. 80, c/a = 0. 45 − 0. 52 and a bulk density of 0. 992 g/cm³. For other uses of the words gram or gramme see Gram (disambiguation. A cubic centimetre or cubic centimeter (symbol cm3 —the abbreviation cc, though widely used is deprecated is a commonly used unit of Volume ^[2] Since the discovery of Varuna, another, even larger, rapidly rotating (3. 9 h) object (136108) 2003 EL₆₁ has been discovered, also thought to have an elongated shape. ^[8]

The surface of Varuna is moderately red (similar to Quaoar) but exceptionally dark (albedo<0. 04) compared with other large classical Kuiper Belt objects, suggesting that the surface is largely devoid of ice, although small amounts of water ice have been detected on its surface ^[9]. In astronomy a classical Kuiper Belt object, also called a cubewano (ˌkjuːbiːˈwɑːnoʊ is a Kuiper belt object that Orbits beyond Neptune The Kuiper belt (ˈkaɪpɚ to rhyme with "viper" sometimes called the Edgeworth-Kuiper belt, is a region of the Solar System beyond the planets extending

References

External links

• Size and Albedo of Kuiper Belt Object (20000) Varuna. David Jewitt's Home Page. Retrieved on 2005-08-15. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. Events 778 - The Battle of Roncevaux Pass, at which Roland is killed Site updated Reretrived on 2006-07-10
• Orbital simulation from JPL (Java) / Ephemeris
• Large TNO occultation possible in Americas Feb. 10/11