52 Europa

52 Europa
VLT-SPHERE image of Europa
Discovery
Discovered byH. Goldschmidt
Discovery date4 February 1858
Designations
Pronunciation/jʊˈroʊpə/[1]
Named after
Europa
1948 LA
Main belt
AdjectivesEuropan, Europian
Orbital characteristics[2]
Epoch July 1, 2021
(JD 2,459,396.5, heliocentric)
Aphelion3.442 AU (515 million km)
Perihelion2.746 AU (411 million km)
3.094 AU (463 million km)
Eccentricity0.1125
5.443 yr (1989 d)
21°
Inclination7.48°
128.57°
342.80°
Physical characteristics
Dimensions(379±16)×(330±8)×(249±10) km[3]
319±4 km[4]
315±7 km[3]
Flattening0.33[a]
Mass(24±4)×1018 kg[4]
(22.6±1.6)×1018 kg[b][5]
Mean density
1.41±0.23 g/cm3[4]
1.5±0.4 g/cm3[3]
5.6304 h[2]
0.057±0.007 geometric (0.679±0.017 BV, 0.338±0.028 UB)[2]
Temperature~173 K
max: 258 K (−15 °C)[6]
C/CF[2]
6.66[2]

52 Europa is the sixth-largest asteroid in the asteroid belt, having a diameter of over 300 km, though it is not correspondingly massive. It is shaped like an ellipsoid with approximate dimensions of 380×330×250 km.[3] It was discovered on 4 February 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.

Orbit

Animation of 52 Europa's orbit 2000–2020
  Sun ·   Earth ·   Mars ·   Jupiter ·   52 Europa

Europa is a main belt asteroid that orbits the Sun at a distance of 2.746–3.442 astronomical units (AU) with a semi-major axis or average orbital distance of 3.094 AU once every 5.44 years[2] (for reference, Ceres's orbit is at 2.77 AU).[7]

Europa's orbit has an eccentricity of 0.1125 and an inclination of 7.482° with respect to the ecliptic.[2]

Physical characteristics

3D model of Europa based on lightcurve modeling

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.[3] In 2007, James Baer and Steven R. Chesley estimated Europa to have a mass of (1.9±0.4)×1019 kg.[8] A more recent estimate by Baer suggests it has a mass of 3.27×1019 kg.[9]

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,[10] and there is some indication that there may be compositional differences between different regions.[11] 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+1⁄2 hours to 11 hours), despite numerous observations.[12] 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.[13] 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 Maunakea Observatories, but the effort came up empty.[14]

Observations

The reputed cataclysmic variable star CV Aquarii, discovered in 1934 by Emily Hughes at Harvard College Observatory, was actually a misidentification of 52 Europa.[15]

Notes

  1. ↑ Flattening derived from the maximum aspect ratio (c/a): , where (c/a) = 0.67±0.04.[4]
  2. ↑ (11.39 ± 0.79) × 10−12 M☉

References

  1. ↑ Webster, Noah (1884). A Practical Dictionary of the English Language
  2. 1 2 3 4 5 6 7 JPL data Retrieved 2021-09-29
  3. 1 2 3 4 5 Merline, W.J. (2013). "The Resolved Asteroid Program – Size, shape, and pole of (52) Europa". Icarus. 225 (1): 794–805. arXiv:1301.5101. Bibcode:2013Icar..225..794M. doi:10.1016/j.icarus.2013.01.010. S2CID 119286695.
  4. 1 2 3 4 P. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis. Astronomy & Astrophysics 54, A56
  5. ↑ James Baer, Steven Chesley & Robert Matson (2011) "Astrometric masses of 26 asteroids and observations on asteroid porosity." The Astronomical Journal, Volume 141, Number 5
  6. ↑ Dotto, E.; Müller, T. G.; Barucci, M. A.; Encrenaz, Th.; Knacke, R. F.; Lellouch, E.; Doressoundiram, A.; Crovisier, J.; Brucato, J. R.; Colangeli, L.; Mennella, V. (2000). "ISO results on bright Main Belt asteroids: PHT-S observations". Astronomy and Astrophysics. 358: 1134. Bibcode:2000A&A...358.1133D. Retrieved 23 February 2024.
  7. ↑ "AstDyS-2 Ceres Synthetic Proper Orbital Elements". Department of Mathematics, University of Pisa, Italy. Archived from the original on 21 November 2011. Retrieved 1 October 2011.
  8. ↑ Baer, James; Chesley, Steven R. (2007). "Astrometric masses of 21 asteroids, and an integrated asteroid ephemeris". Celestial Mechanics and Dynamical Astronomy. 100 (2008). Springer Science+Business Media B.V. 2007: 27–42. Bibcode:2008CeMDA.100...27B. doi:10.1007/s10569-007-9103-8.
  9. ↑ Baer, James (2008). "Recent Asteroid Mass Determinations". Personal Website. Archived from the original on 2 July 2013. Retrieved 29 November 2008.
  10. ↑ Dotto, E. (2000). "ISO results on bright Main Belt asteroids: PHT–S observations" (PDF). Astronomy & Astrophysics. 358: 1133. Bibcode:2000A&A...358.1133D. Archived from the original (PDF) on 14 May 2005. Retrieved 29 April 2006.
  11. ↑ Sawyer, Scott Raleigh (1 January 1991). "A High-Resolution CCD Spectroscopic Survey of Low-Albedo Main Belt Asteroids". PhD Thesis. Bibcode:1991PhDT.......105S – via NASA ADS.
  12. ↑ Zappalà, V.; di Martino, M.; Cacciatori, S (1983). "On the ambiguity of rotational periods of asteroids: The peculiar case of 52 Europa". Icarus. 56 (2): 319–324. Bibcode:1983Icar...56..319Z. doi:10.1016/0019-1035(83)90041-6.
  13. ↑ 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.
  14. ↑ 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, vol. 19, pp. 405–406, Bibcode:1988LPI....19..405G.
  15. ↑ Schmeer, Patrick; Hazen, Martha L. "CV Aquarii identified with (52) Europa" (PDF). Journal of the American Association of Variable Star Observers. 28: 103–105. Bibcode:2000JAVSO..28..103S. Archived from the original (PDF) on 14 February 2006. Retrieved 29 April 2006.

Bibliography

  • PDS lightcurve data[link removed]
  • Sawyer, S. R. (1991). A High-Resolution CCD Spectroscopic Survey of Low-Albedo Main Belt Asteroids PhD thesis (Thesis). The University of Texas. Bibcode:1991PhDT.......105S.
  • 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).
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