532 Herculina is a large main belt asteroid, with a diameter of around 222 km. Herculina is the 18th largest asteroid currently known.
Discovery
Herculina was discovered on April 20, 1904, by Max Wolf in Heidelberg.
Naming
Herculina was initially catalogued as 1904 NY.
The origin of Herculina's name was lost. The asteroid may be named after the mythical Hercules, or after an unknown woman of that name. The bulk of the asteroids discovered by Wolf around this date were named for characters in operas, but if this name was also drawn from such a source, no explanation has been recorded.
Stats
Diameter (mean): 222 km
Aphelion: 3.26 AU
Perihelion: 2.278 AU
Semi-major axis: 2.77 AU
Orbital Period: 4.61 years
Rotation period: 9.405 hrs
Date discovered: 1904.4.20
Class: S
Type: Main-belt Asteroid
(data from JPL Small-Body Database)
Physical characteristics
Herculina has often been noted for its complex lightcurves, which made determination of its shape and rotation somewhat difficult.
Recent modelling in 2002 of photometric data indicates that Herculina is not spherical, but a blocky shape not unlike a battered cuboid - or, as the analysis described it, it "resembles a toaster". This analysis indicates the presence of multiple large craters, but no major variation in albedo. The approximate ratios of the axes were suggested as 1:1.1:1.3, broadly consistent with earlier models if slightly more elongated.
Satellite (S/1978(532)1) ?
Following anomalous observations during an occultation of the star SAO 120774 in 1978, Herculina became the first asteroid to be "confirmed" to have an asteroid moon. A satellite of about 45 km orbiting at a distance of about 1,000 km from Herculina.
However, careful examination in 1993, using the Hubble Space Telescope, failed to locate the moon.
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