Asteroid 2, the second asteroid to be discovered, by H. W. M. Olbers in 1802. Its shape is a triaxial ellipsoid, 582 × 556 × 500 km, giving a mean diameter similar to that of Vesta; its rotation period is 7.81 h. Its mass is 3.2 × 1020kg, also similar to that of Vesta, and its density is 4.2. Pallas is of B type, with a spectrum similar to that of the carbonaceous chondrite meteorites. Its mean magnitude at opposition is 8.0; only Vesta and Ceres can become brighter. Its orbit has a semimajor axis of 2.77 au, period 4.62 years, perihelion 2.13 au, aphelion 3.41 au, and an unusually high inclination of 34°.8.