Europa (minor planet designation: 52 Europa) is the 6th-largest asteroid in the asteroid belt, having a diameter of over 300km, though it is not correspondingly massive. It is not round but is shaped like an ellipsoid of approximately 380×330×250km.[4] 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.
Large asteroid in the asteroid belt
For the moon of Jupiter, see Europa (moon). For other uses, see Europa (disambiguation).
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.[4] In 2007, James Baer and Steven R. Chesley estimated Europa to have a mass of (1.9±0.4)×1019kg.[7] A more recent estimate by Baer suggests it has a mass of 3.27×1019 kg.[8]
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,[9] and there is some indication that there may be compositional differences between different regions[10] 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.[11] 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.[12] 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.[13]
Observations
It has been found that the reputed cataclysmic variable star CV Aquarii, discovered in 1934, was actually a misidentification of 52 Europa.[14]
Animation of 52 Europa's orbit 2000–2020 Sun Earth· Mars·Jupiter· 52 Europa
Notes
(11.39 ± 0.79) × 10−12M☉
References
Noah Webster (1884) A Practical Dictionary of the English Language
James Baer, Steven Chesley & Robert Matson (2011) "Astrometric masses of 26 asteroids and observations on asteroid porosity." The Astronomical Journal, Volume 141, Number 5
"Archived copy"(PDF). Archived from the original(PDF) on 14 May 2005. Retrieved 29 April 2006.{{cite web}}: CS1 maint: archived copy as title (link)
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.
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.
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.
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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