52 Europa
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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
- ↑ 1.0 1.1 1.2 1.3 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ http://www.rni.helsinki.fi/~mjk/Micha.pdf
- ↑ 4.0 4.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ http://www.psi.edu/pds/archive/lc.html
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ http://aa.springer.de/papers/0358003/2301133.pdf
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1991PhDT.......105S&db_key=AST&data_type=HTML&format=&high=444b66a47d24766
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ http://www.aavso.org/publications/ejaavso/v28n2/103.pdf
Bibliography
- PDS lightcurve data
- Lua error in package.lua at line 80: module 'strict' not found.
- 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
- Lua error in package.lua at line 80: module 'strict' not found.
- shape model deduced from lightcurve
