5Astraea (Lightcurve Inversion)
Adjective(s) Unknown
Orbital properties
Aphelion/apoapsis 3.065755252 AU (459.202 Gm)
Perihelion/periapsis 2.08186277 AU (310.688 Gm)
Semi-major axis 2.573809012 AU (384.945 Gm)
Orbital eccentricity 0.19113549
Orbital period 4.129264267 a (1508.213773 d)
Average orbital speed 18.39 km/s
Physical properties
Radius Unknown
Mass 2.9×1018 kg


Mean density ~3.3 g/cm³
Escape velocity ~0.062 km/s
Rotation period 0.700 03 d (16.801 h)
Average surface temperature ~167 K

max: 263 K (-10 °C) (13.730000000000018 °F)

Apparent magnitude 8.74 to 12.89
Moons 0

5 Astraea is a large asteroid from the asteroid belt. Its surface is highly reflective (bright) and its composition is probably a mixture ofnickel–iron with silicates of magnesium and iron. It was the 5th asteroid discovered (December 8, 1845) by  K. L. Hencke and named for Astræa, a goddess of justice named after the stars. It was his first of two asteroid discoveries. The second was 6 Hebe.