532 Herculina (herr'-kew-lye'-nə, ) is a very large asteroid, with a diameter of around 225 km.
It has often been noted for its complex lightcurves, which made determination of its shape and rotation somewhat difficult. A set of 1982 speckle inferometry observations led to a simple preliminary model of Herculina as a three-axis object, perhaps 260 by 220 by 215 km. 1985 analysis of this data concluded there was a nonspherical shape with one bright spot, whilst a 1987 photometric astrometry study concluded the object was spherical with two dark spots (and rotated around a completely different pole), which was in turn negated by a 1988 thermal study which showed the object could not be spherical. By the late 1980s, the generally accepted model was a three-axis object with major albedo or topographical features.
Recent (2002) modelling 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 largish craters, similar to 253 Mathilde, 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.