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Discovery
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| Discovered by | Ernst Wilhelm Tempel |
| Discovery date | March 4, 1861 |
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Designations
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| Alternate name(s) | |
| Minor planet category |
Main belt[1] |
| Epoch December 31, 2006 (JD 2454100.5) | |
| Aphelion | 451.375 Gm (3.017 AU) |
| Perihelion | 351.784 Gm (2.352 AU) |
| Semi-major axis | 401.580 Gm (2.684 AU) |
| Eccentricity | 0.124 |
| Orbital period | 1606.452 d (4.40 a) |
| Average orbital speed | 18.11 km/s |
| Mean anomaly | 107.758° |
| Inclination | 1.308° |
| Longitude of ascending node | 309.285° |
| Argument of perihelion | 179.641° |
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Physical characteristics
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| Dimensions | 48x53 km[2] |
| Mass | ?×10? kg |
| Mean density | ? g/cm³ |
| Equatorial surface gravity | ? m/s² |
| Escape velocity | ? km/s |
| Rotation period | 8.752 hr[1] (0.365 d) |
| Albedo | 0.28[3] 0.157 (IRAS)[1] |
| Temperature | ~170 K |
| Spectral type | E |
| Absolute magnitude (H) | 7.67[1] |
64 Angelina is a medium-sized main belt E-type asteroid discovered in 1861. It is an unusually bright form of E-type asteroid.
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Angelina was discovered on March 4, 1861, by a prolific comet discoverer, E. W. Tempel, observing from Marseilles, France. It was the first of his five asteroid discoveries.
Angelina's name caused some controversy. It was chosen by Benjamin Valz, 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, a minor Greek deity). However, Valz's choice stayed.[4]
Angelina is an uncommon form of E-type asteroid; it is the third largest E-type after 44 Nysa and 55 Pandora, and has an exceptionally high albedo.[5] As of 1991, it is thought to have an average radius of about 30 kilometers (19 mi).[6] Back when asteroids were generally assumed to have low albedos, 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 of 7.7 and an albedo of 0.15,[1] its diameter would have been around 100 km. However, a 2004 occultation showed a cross-sectional profile of only 48x53 km.[2] However, since an occultation only produces a 2D cross-sectional profile of the shape of an asteroid, it is possible that the primary axis of the asteroid was hidden from view during the occultation.
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