52 Europa

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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 not round but is shaped like an ellipsoid of approximately 380×330×250 km.<ref name="Merline">Template:Cite journal</ref> 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.

Physical characteristics

File:52 Europa Lightcurve Inversion.png

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.<ref name=Merline/> In 2007, James Baer and Steven R. Chesley estimated Europa to have a mass of Template:Val kg.<ref name="Baer2007">Template:Cite journal</ref> A more recent estimate by Baer suggests it has a mass of 3.27Template:E kg.<ref name=Baer> Template:Cite web </ref>

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,<ref name=Dotto00 /> and there is some indication that there may be compositional differences between different regions.<ref>Template:Cite journal</ref> 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 Template:Frac hours to 11 hours), despite numerous observations.<ref name=Zappala83 /> 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.<ref name=Michalowski04 /> 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.<ref name="Gradie1988">Template:Citation</ref>

Observations

It has been found that the reputed cataclysmic variable star CV Aquarii, discovered in 1934, was actually a misidentification of 52 Europa.<ref>Template:Cite web</ref>

File:Animation of 52 Europa orbit 2000-2020.gif

Animation of 52 EuropaTemplate:'s orbit 2000–2020
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Notes

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References

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Bibliography

PDS lightcurve data
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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

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