 | |
| Discovery | |
|---|---|
| Discovered by | H. Goldschmidt |
| Discovery date | 4 February 1858 |
| Designations | |
| (52) Europa | |
| Pronunciation | /jʊˈroʊpə/[1] |
Named after | Europa |
| 1948 LA | |
| Main belt | |
| Adjectives | Europan, Europian |
| Orbital characteristics[2] | |
| Epoch July 01, 2021 (JD 2459396.5, heliocentric) | |
| Aphelion | 3.444AU (510 Gm) |
| Perihelion | 2.75 AU (420 Gm) |
| 3.095 AU (460 Gm) | |
| Eccentricity | 0.111 |
| 5.45yr (1989 d) | |
| 21° | |
| Inclination | 7.48° |
| 129° | |
| 343° | |
| Physical characteristics | |
| Dimensions | (379±16)×(330±8)×(249±10) km[3] |
| 319±4 km[4] 315±7 km[3] | |
| Flattening | 0.33[a] |
| Mass | (24±4)×1018 kg[4] (22.6±1.6)×1018 kg[b][5] |
Meandensity | 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 | ~173K max: 258K (−15 °C)[6] |
| C/CF[2] | |
| 6.66[2] | |
52 Europa is thesixth largestasteroid in theasteroid belt, having a diameter of over 300 km, though it is not correspondingly massive. It is not spherical but is shaped like an ellipsoid of approximately 380×330×250 km.[3] It was discovered on 4 February 1858, byHermann Goldschmidt from his balcony inParis. It is named afterEuropa, one ofZeus's conquests inGreek mythology, a name it shares withJupiter's moonEuropa.
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.[7] A more recent estimate by Baer suggests it has a mass of 3.27×1019 kg.[8]
Europa is a very dark carbonaceousC-type, and is the second largest of this group. Spectroscopic studies have found evidence ofolivines andpyroxenes on the surface,[9] and there is some indication that there may be compositional differences between different regions.[10] It orbits close to theHygiea 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 from5+1⁄2 hours to 11 hours), despite numerous observations.[11] It has now been determined that Europa is aprograde rotator, but the exact direction in which its pole points remains ambiguous. The most detailed analysis indicates that it points either towards aboutecliptic coordinates (β, λ) = (70°, 55°) or (40°, 255°) with a 10° uncertainty.[12] This gives anaxial tilt of about 14° or 54°, respectively.
In 1988 a search for satellites or dust orbiting this asteroid was performed using theUH88 telescope at theMauna Kea Observatories, but the effort came up empty.[13]
It has been found that the reputedcataclysmic variable star CV Aquarii, discovered in 1934, was actually a misidentification of 52 Europa.[14]
