- This article is about the minor planet Europa. For other uses, see Europa (disambiguation).
Europa, minor planet designation 52 Europa, is an asteroid located in the asteroid belt that was discovered by Hermann Goldschmidt on February 4, 1858. It is the 6th-largest asteroid in the asteroid belt and has a diameter of around 315 km, though it is not massive. It is not spherical, and is instead shaped like an ellipsoid of approximately 380 × 330× 250 km. The asteroid was named after Europa, daughter of King Agenor, one of Zeus's conquests in Greek mythology. It shares a name with the Jupiter 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, which are typical of C-type asteroids. In 2007, James Baer and Steven R. Chesley estimated Europa to have a mass of 1.9 x 1019 kg. More recent estimates from Baer suggests a mass of 3.27 1019 kg.
Europa is a very dark C-type carbonate asteroid, and is the second largest of its group. Spectroscopic studies have found evidence of olivines and proyxenes on its surface, and there are some indications that the celestial body is composed of different regions of different compositions. Europa orbits the Sun at a distance close to the asteroids of the Hygiea asteroid family, but it is not a member.
The data from the Europa lightcurve was particularly difficulty to interpret, so much so that for many years, there was some doubt about its rotation period (ranging from 5.5 hours to 11 hours), despite its numerous observations. It has now been determined with certainy that Europa is a prograde rotator, but the exact direction in which its pole points are oriented remains ambiguous. The most detailed analysis indicates that they point either to the point of ecliptic coordinates (β, λ) = (70°, 55°) or (40°, 255°), with an uncertainty of 10°. This gives an axial tilt of approximately 14° or 54°, respectively.
In 1988, a search for satellites and dust orbiting this asteroid was performed using the Mauna Kea Observatories' UH88 telescope, but the effort was unsuccessful.
Observations[]
It was found that the reputed cataclysmic variable star CV Aquarii, discovered in 1934, was actually a misidentification of Europa.