52 Europa
|
3D model of Europa based on lightcurve modeling | |
| Discovery | |
|---|---|
| Discovered by | H. Goldschmidt |
| Discovery date | February 4, 1858 |
| Designations | |
| Pronunciation | /jʊˈroʊpə/ ew-ROH-pə |
Named after | Europa |
| 1948 LA | |
| Main belt | |
| Orbital characteristics | |
| Epoch November 26, 2005 (JD 2453700.5) | |
| Aphelion | 3.417 AU (511.201 Gm) |
| Perihelion | 2.785 AU (416.621 Gm) |
| 3.101 AU (463.911 Gm) | |
| Eccentricity | 0.102 |
| 5.46 yr (1994.629 d) | |
Average orbital speed | 16.87 km/s |
| 70.730° | |
| Inclination | 7.466° |
| 128.992° | |
| 343.553° | |
| Physical characteristics | |
| Dimensions |
(379±16)×(330±8)×(249±10) km (mean: 315±7 km)[1] 360×315×240 km[2][3] |
| Mass | 3.27×1019 kg[4] |
Mean density | 1.5 ± 0.4 g/cm³[1] |
| ~0.14 m/s² | |
| ~0.2 km/s | |
| 0.2347 d[5] | |
| Albedo | 0.058[6] |
| Temperature |
~173 K max: 258K (−15 °C)[7] |
Spectral type | C-type asteroid |
| 6.31 | |
|
| |
52 Europa is the 6th-largest asteroid in the asteroid belt, having an average diameter of around 315 km. It is not round but is shaped like a triaxial ellipsoid of approximately 380x330x250 km.[1] It was discovered on February 4, 1858, by Hermann Goldschmidt from his balcony in Paris. It is named after Europa, one of Zeus's conquests in Greek mythology, a name it shares with Jupiter's moon Europa.
Physical characteristics
Europa is approximately the sixth largest asteroid by volume. Most likely it has a density of around 1.5 g/cm³, typical of C-type asteroids.[1] In 2007, James Baer and Steven R. Chesley estimated Europa to have a mass of (1.9±0.4)×1019 kg.[2] A more recent estimate by Baer suggests it has a mass of 3.27×1019 kg.[4]
Europa is a very dark carbonaceous C-type, and is the second largest of this group. Spectroscopic studies have found evidence of olivines and pyroxenes on the surface,[8] and there is some indication that there may be compositional differences between different regions[9] It orbits close to the Hygiea asteroid family, but is not a member.
Lightcurve data for Europa have been particularly tricky to interpret, so much so that for a long time its period of rotation was in dispute (ranging from 5 and a half hours to 11 hours), despite numerous observations.[10] It has now been determined that Europa is a prograde rotator, but the exact direction in which its pole points remains ambiguous. The most detailed analysis indicates that it points either towards about ecliptic coordinates (β, λ) = (70°, 55°) or (40°, 255°) with a 10° uncertainty.[11] This gives an axial tilt of about 14° or 54°, respectively.
In 1988 a search for satellites or dust orbiting this asteroid was performed using the UH88 telescope at the Mauna Kea Observatories, but the effort came up empty.[12]
Observations
It has been found that the reputed cataclysmic variable star CV Aquarii, discovered in 1934, was actually a misidentification of 52 Europa.[13]
References
- 1 2 3 4 Merline, W.J. (2013). "The Resolved Asteroid Program - Size, shape, and pole of (52) Europa". arXiv:1301.5101
. - 1 2 Baer, James; Steven R. Chesley (2007). "Astrometric masses of 21 asteroids, and an integrated asteroid ephemeris" (PDF). Celestial Mechanics and Dynamical Astronomy. Springer Science+Business Media B.V. 2007. 100 (2008): 27–42. Bibcode:2008CeMDA.100...27B. doi:10.1007/s10569-007-9103-8. Retrieved 2008-11-15.
- ↑ "Helsingin yliopisto - Matematiikan ja tilastotieteen laitos" (PDF).
- 1 2 Baer, James (2008). "Recent Asteroid Mass Determinations". Personal Website. Retrieved 2008-11-29.
- ↑ "Archived copy". Archived from the original on 2006-06-14. Retrieved 2008-11-03.
- ↑ Tedesco, Edward F.; Noah, Paul V.; Noah, Meg; Price, Stephan D. (2002). "The Supplemental IRAS Minor Planet Survey". The Astronomical Journal. The American Astronomical Society. 123 (2): 1056–85. Bibcode:2002AJ....123.1056T. doi:10.1086/338320. ISSN 1538-3881.
- ↑ http://aa.springer.de/papers/0358003/2301133.pdf
- ↑ Dotto, E. (2000). "ISO results on bright Main Belt asteroids: PHT–S observations" (PDF). Astronomy & Astrophysics. 358: 1133. Bibcode:2000A&A...358.1133D.
- ↑ Sawyer, Scott Raleigh (1 January 1991). "A High-Resolution CCD Spectroscopic Survey of Low-Albedo Main Belt Asteroids.". Ph.D. Thesis – via NASA ADS.
- ↑ Zappalà, V.; di Martino, M.; Cacciatori, S (1983). "On the ambiguity of rotational periods of asteroids: The peculiar case of 52 Europa". Icarus. 56: 319–324. Bibcode:1983Icar...56..319Z. doi:10.1016/0019-1035(83)90041-6.
- ↑ Michałowski, T (2004). "Photometry and models of selected main belt asteroids I. 52 Europa, 115 Thyra, and 382 Dodona" (PDF). Astronomy & Astrophysics. 416: 353–366. Bibcode:2004A&A...416..353M. doi:10.1051/0004-6361:20031706.
- ↑ Gradie, J.; Flynn, L. (March 1988), "A Search for Satellites and Dust Belts Around Asteroids: Negative Results", Abstracts of the Lunar and Planetary Science Conference, 19, pp. 405–406, Bibcode:1988LPI....19..405G.
- ↑ "Archived copy" (PDF). Archived from the original (PDF) on 2006-02-14. Retrieved 2006-04-29.
Bibliography
- PDS lightcurve data
- Sawyer, S. R. (1991). A High-Resolution CCD Spectroscopic Survey of Low-Albedo Main Belt Asteroids PhD thesis (Thesis). The University of Texas.
- Schmeer, P., and M. L. Hazen, CV Aquarii identified with (52) Europa, Journal of the American Association of Variable Star Observers, Vol. 28, p. 103 (2000).
External links
- "Elements and Ephemeris for (52) Europa". Retrieved 2011-05-26.
- shape model deduced from lightcurve
- 52 Europa at the JPL Small-Body Database
