Английская Википедия:791 Ani

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791 Ani (prov. designation: Шаблон:Mp or Шаблон:Mp) is a very large asteroid of the Meliboea family, located in the outer regions of the asteroid belt. It was discovered on 29 June 1914, by Russian astronomer Grigory Neujmin at the Simeiz Observatory on the Crimean peninsula. The dark carbonaceous C-type asteroid has a rotation period of 11.2 hours and measures approximately Шаблон:Val kilometers, with a mean-diameter of Шаблон:Convert. It was named after the historic Armenian city of Ani.

Orbit and classification

When applying the hierarchical clustering method (HCM) to its proper orbital elements, Ani is a member of the Meliboea family (Шаблон:Small), a small family of carbonaceous asteroids in the outer main belt, named after its principal body, 137 Meliboea.Шаблон:Rp However, according to another HCM-analysis by Milani and Knežević (AstDyS), it is a background asteroid as this analysis does not recognize the Meliboea family. Ani orbits the Sun in the outer asteroid belt at a distance of 2.5–3.7 AU once every 5 years and 6 months (2,015 days; semi-major axis of 3.12 AU). Its orbit has an eccentricity of 0.19 and an inclination of 16° with respect to the ecliptic. The body's observation arc begins at Algiers Observatory in North Africa on 6 December 1915, some 17 months after its official discovery observation at Simeiz Observatory.

Naming

This minor planet was named after the medieval city of Ani, which was destroyed by an earthquake in 1319. The ruins of the former capital of the Armenian kingdom are located near the border to Armenia, in what is now Turkey. Ani was known as "the city of 1001 churches". The Шаблон:MoMP was also mentioned in The Names of the Minor Planets by Paul Herget in 1955 (Шаблон:Small).

Physical characteristics

In the Tholen classification, Ani is a common, carbonaceous C-type asteroid. It is also a common C-type in the Tholen-like taxonomy of the Small Solar System Objects Spectroscopic Survey (S3OS2), while in the survey's SMASS-like taxonomic variant, the asteroid is a hydrated carbonaceous subtype (Ch).

Rotation period and poles

In May 2018, a rotational lightcurve of Ani was obtained from photometric observations by American amateur astronomer Tom Polakis at the Command Module Observatory Шаблон:Obscode in Arizona . Lightcurve analysis gave a well-defined rotation period of Шаблон:Val hours with a brightness variation of Шаблон:Val magnitude (Шаблон:Small).

In June 2002, Brian Warner at his Palmer Divide Observatory first observed this asteroid and later derived a period of Шаблон:Val hours and an amplitude of Шаблон:Val magnitude, based on poor data (Шаблон:Small).Шаблон:Efn In December 2004, and in May 2007, two periods of Шаблон:Val and Шаблон:Val with a corresponding amplitude of Шаблон:Val and Шаблон:Val magnitude were determined by European astronomers Raymond Poncy Шаблон:Obscode as well as Yves Revaz, Raoul Behrend, Alain Klotz, Michel Hernandez, Robert Soubie, Jean-François Gauthier, Bernard Tregon, Pierre Antonini, Laurent Bernasconi, Federico Manzini Шаблон:Obscode, Yassine Damerdji and Horacio Correia. The two periods are slightly longer than twice PolakisШаблон:' period solution (Шаблон:Small). In April 2007, astronomers at the Oakley Observatory Шаблон:Obscode, Indiana, obtained a period of Шаблон:Val hours and an amplitude of Шаблон:Val magnitude (Шаблон:Small). In February 2011, French amateur astronomer René Roy determined a period of Шаблон:Val hours and a brightness variation of Шаблон:Val magnitude (Шаблон:Small).

A modeled lightcurve by Josef Ďurech and Josef Hanuš, using photometric data including from the Lowell Photometric Database and from the Wide-field Infrared Survey Explorer (WISE) was published in 2018. It gave a sidereal period of Шаблон:Val and two spin axes at (94.0°, −25.0°) and (269.0°, 4.0°) in ecliptic coordinates (λ, β).

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite, the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), and the Infrared Astronomical Satellite IRAS, Ani measures (Шаблон:Val), (Шаблон:Val) and (Шаблон:Val) kilometers in diameter and its surface has an albedo of (Шаблон:Val), (Шаблон:Val) and (Шаблон:Val), respectively. The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.0329 and a diameter of 103.52 kilometers based on an absolute magnitude of 9.25. Alternative mean-diameter measurements published by the WISE team include (Шаблон:Val), (Шаблон:Val), (Шаблон:Val) and (Шаблон:Val) with corresponding albedos of (Шаблон:Val), (Шаблон:Val), (Шаблон:Val) and (Шаблон:Val). On 7 April 2000, an asteroid occultation of Ani gave a best-fit ellipse dimension of (Шаблон:Val) with a good quality rating of 3. These timed observations are taken when the asteroid passes in front of a distant star.

External links

• Lightcurve Database Query (LCDB), at www.minorplanet.info
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Geneva Observatory, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• Шаблон:AstDys
• Шаблон:JPL small body