64 Angelina

64 Angelina
Lightcurve-based 3D model of Angelina
Discovery
Discovered byErnst Wilhelm Tempel
Discovery date4 March 1861
Designations
Pronunciation/ˌændʒəˈliːnə/ AN-jə-LEE-nə
Main belt
AdjectivesAngelinian (/ˌændʒəˈlɪniən/ AN-jə-LIN-nee-ən)
Orbital characteristics
Epoch 31 December 2006 (JD 2,454,100.5)
Aphelion451.375 million km (3.017 AU)
Perihelion351.784 million km (2.352 AU)
401.580 million km (2.684 AU)
Eccentricity0.124
1,606.452 d (4.40 yr)
107.758°
Inclination1.308°
309.285°
179.641°
Physical characteristics
Dimensions48 × 53 km
52 ± 10 km
60 × 53 × 45 km
Mass1.5×1017 kg (assumed)
8.752 hr (0.365 d)
0.28
0.483 (NEOWISE)
E
7.67

64 Angelina is an asteroid in the central region of the asteroid belt, approximately 50 kilometres in diameter. It is the second-largest known E-type asteroid, a rare type of asteroid with a highly reflective surface rich in enstatite.

Discovery and naming

Angelina was discovered on 4 March 1861, by a prolific comet discoverer, E. W. Tempel, observing from Marseille, France. It was the first of his five asteroid discoveries.[citation needed]

The naming of Angelina caused some controversy. It was chosen by Benjamin Valz, director of the Marseille 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 against 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.

Physical characteristics

Angelina is a E-type asteroid, a rare type of asteroid with a reflective surface rich in enstatite. It has a diameter of approximately 50 km (31 mi), making it the second-largest known E-type asteroid after 44 Nysa. Angelina has an exceptionally high albedo of 0.483.

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, its diameter would have been around 100 km. However, a 2004 occultation showed a cross-sectional profile of only 48 × 53 km. Angelina was observed by Arecibo radar in January 2010.

References

  1. ↑ "Angelina". Oxford English Dictionary (online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  2. 1 2 3 4 5 6 "JPL Small-Body Database Browser: 64 Angelina". Retrieved 5 September 2010. 2010-06-01 last obs
  3. 1 2 Dunham, David (2–3 July 2004). "IOTA Meeting, Apple Valley, Calif". IOTA. Retrieved 21 February 2007.
  4. ↑ 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:1104.4227. Bibcode:2011Icar..214..652D. doi:10.1016/j.icarus.2011.03.016. S2CID 119271216. Archived from the original (PDF) on 3 March 2016. Retrieved 26 January 2012.
  5. 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. arXiv:1104.4114. Bibcode:2011Icar..215..547S. doi:10.1016/j.icarus.2011.07.027. S2CID 119290080.
  6. ↑ Using a spherical radius of 26 km; volume of a sphere * density of 2 g/cm3 yields a mass (m=d*v) of 1.472×1017 kg
  7. ↑ 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.
  8. 1 2 3 Shevchenko, V.G.; Krugly, Yu.N.; Chiorny, V.G.; Belskaya, I.N.; Gaftonyuk, N.M. (August 2003). "Rotation and photometric properties of E-type asteroids". Planetary and Space Science. 51 (9–10): 525–532. doi:10.1016/S0032-0633(03)00076-X.
  9. ↑ Schmadel, Lutz D. (2003). Dictionary of Minor Planet Names. Springer Science & Business Media. p. 21. ISBN 978-3-540-00238-3.
  10. ↑ Kiselev, N. N.; Shakhovskoy, N. M.; Efimov, Yu. S. (1996), "On the Polarization Opposition Effect of E-Type Asteroid 64 Angelina", Icarus, 120 (2): 408, Bibcode:1996Icar..120..408K, doi:10.1006/icar.1996.0060