64 Angelina

64 Angelina

A three-dimensional model of 64 Angelina
based on its light curve
Discovery
Discovered by Ernst Wilhelm Tempel
Discovery date March 4, 1861
Designations
 
Main belt[1]
Orbital characteristics
Epoch December 31, 2006 (JD 2454100.5)
Aphelion 451.375 Gm (3.017 AU)
Perihelion 351.784 Gm (2.352 AU)
401.580 Gm (2.684 AU)
Eccentricity 0.124
1606.452 d (4.40 yr)
18.11 km/s
107.758°
Inclination 1.308°
309.285°
179.641°
Physical characteristics
Dimensions 48 x 53 km[2]
52 ± 10 km[3]
60 x 53 x 45 km[4]
Mass 1.5×1017 kg (assumed)[5]
Mean density
 ? g/cm³
? m/s²
? km/s
8.752 hr[1] (0.365 d)
Albedo 0.28 [6]
0.157 (IRAS)[1]
Temperature ~ 170 K
Spectral type
 E
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.

    Discovery and naming

    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.[7]

    Physical characteristics

    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.[8] As of 1991, it is thought to have an average radius of about 30 kilometers (19 mi).[9] 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] Angelina was observed by Arecibo radar in January 2010.[4]

    References

    1. 1 2 3 4 5 "JPL Small-Body Database Browser: 64 Angelina". Retrieved 2010-09-05. 2010-06-01 last obs
    2. 1 2 David Dunham (July 2–3, 2004). "IOTA Meeting, Apple Valley, Calif.". IOTA. Retrieved 2007-02-21.
    3. ↑ Ďurech, Josef; Kaasalainen, Mikko; Herald, David; Dunham, David; Timerson, Brad; Hanuš, Josef; et al. (2011). "Combining asteroid models derived by lightcurve inversion with asteroidal occultation silhouettes" (PDF). Icarus. 214 (2): 652–670. arXiv:1104.4227Freely accessible. Bibcode:2011Icar..214..652D. doi:10.1016/j.icarus.2011.03.016.
    4. 1 2 Shepard, Michael K.; Harris, Alan W.; Taylor, Patrick A.; Clark, Beth Ellen; Ockert-Bell, Maureen; Nolan, Michael C.; et al. (2011). "Radar observations of Asteroids 64 Angelina and 69 Hesperia" (PDF). Icarus. 215 (2): 547–551. Bibcode:2011Icar..215..547S. doi:10.1016/j.icarus.2011.07.027.
    5. ↑ Using a spherical radius of 26 km; volume of a sphere * density of 2 g/cm³ yields a mass (m=d*v) of 1.472E+17 kg
    6. ↑ Morrison, D.; Chapman, C. R. (1976). "Radiometric diameters for an additional 22 asteroids". Astrophysical Journal. 204: 934–939. Bibcode:1976ApJ...204..934M. doi:10.1086/154242.
    7. ↑ Lutz D. Schmadel, Dictionary of Minor Planet Names, p.21.
    8. ↑ "On the Polarization Opposition Effect of E-Type Asteroid 64 Angelina", N. N. Kiseleva, N. M. Shakhovskoyb and Yu. S. Efimovb, Astronomical Observatory of Kharkov University, Sumskaya st., 35, Kharkov, 310022, Ukrainef1b Crimean Astrophysical Observatory, Nauchny, 334413, Ukraine ScienceDirect article
    9. ↑ 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)

    External links

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