Angelina (

minor planet designation A formal minor-planet designation is, in its final form, a number–name combination given to a minor planet (asteroid, centaur, trans-Neptunian object and dwarf planet but not comet). Such designation always features a leading number (catalog or ...

: 64 Angelina) is an

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. ...

from the central region of the

asteroid belt The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...

, approximately 50 kilometers in diameter. It is an unusually bright form of

E-type asteroid E-type asteroids are asteroids thought to have enstatite (MgSiO3) achondrite surfaces. They form a large proportion of asteroids inward of the asteroid belt known as Hungaria asteroids, but rapidly become very rare as the asteroid belt proper i ...

Discovery and naming

Angelina was discovered on March 4, 1861, by a prolific

comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...

discoverer, E. W. Tempel, observing from

Marseilles Marseille ( , , ; also spelled in English as Marseilles; oc, Marselha ) is the prefecture of the French department of Bouches-du-Rhône and capital of the Provence-Alpes-Côte d'Azur region. Situated in the camargue region of southern Franc ...

, France. It was the first of his five asteroid discoveries. The naming of Angelina caused some controversy. It was chosen by

Benjamin Valz Jean Elias Benjamin Valz (May 27, 1787 – April 22, 1867) was a French astronomer. He was born in Nîmes and trained as an engineer. He was the son of politician Jean Valz and the grandson of the doctor, meteorologist and naturalist Pierre ...

, director of the Marseilles Observatory, in honour of the astronomical station of that name operated by Baron Franz Xaver von Zach on the mountains above the city. At the time, asteroids were supposed to receive names from classical mythology, and several astronomers protested the choice. Tempel noted that if the second 'n' were removed, the complaints would be satisfied (referring to

Angelia In a poem by the Greek poet Pindar (5th-century BC), Angelia (Ancient Greek: Ἀγγελία ('Message') is mentioned as a daughter of the Greek messenger-god Hermes, where she is understood as "message" personified.A Greek–English Lexicons.v. ...

, a minor Greek deity). However, Valz's choice stayed.

Physical characteristics

Angelina is an uncommon form of

; it is the third largest E-type after

44 Nysa Nysa ( minor planet designation: 44 Nysa) is a large and very bright main-belt asteroid, and the brightest member of the Nysian asteroid family. It is classified as a rare class E asteroid and is probably the largest of this type (though 55 P ...

and 55 Pandora, and has an exceptionally high

albedo Albedo (; ) is the measure of the diffuse reflection of sunlight, solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body ...

. As of 1991, it is thought to have an average radius of about .Lionel Wilson and Klaus Keil - Explosive Eruptions on Asteroids: The Missing Basalts on the Aubrite Parent Body - Abstracts of the Lunar and Planetary Science Conference, volume 22, page 1515, (1991)
/ref> Back when asteroids were generally assumed to have low

s, Angelina was thought to be the largest of this class, but modern research has shown that its diameter is only a quarter of what was previously assumed, an error caused by its exceptional brightness. Traditional calculations had suggested that since Angelina has an

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent mag ...

of 7.7 and an

of 0.15, its diameter would have been around 100 km. However, a 2004

occultation An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks ...

showed a cross-sectional profile of only 48x53 km. Angelina was observed by

Arecibo Arecibo (; ) is a city and municipality on the northern coast of Puerto Rico, on the shores of the Atlantic Ocean, located north of Utuado and Ciales; east of Hatillo; and west of Barceloneta and Florida. It is about west of San Juan, the ...

radar Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...

in January 2010.

References

External links

2004 Angelina occultation
(cross-sectional profile of 48x53 km) * * {{DEFAULTSORT:Angelina 000064 Discoveries by Wilhelm Tempel Named minor planets 000064 000064 18610304