Discovered by James Craig Watson Alternative names 1927 CV, 1950 CM Observation arc 144.99 yr (52958 d) Orbits Sun Discoverer James Craig Watson Discovery site Detroit Observatory | Discovery date 7 September 1868 Minor planet category Main belt Discovered 7 September 1868 Spectral type S-type asteroid Named after Hera | |
Aphelion 2.92042 AU (436.889 Gm) Similar 80 Sappho, 114 Kassandra, 399 Persephone, 128 Nemesis, 161 Athor | ||
103 Hera is a moderately large main-belt asteroid that was discovered by Canadian-American astronomer James Craig Watson on September 7, 1868, and named after Hera, queen and fifth in power of the Olympian gods in Greek mythology. It is an S-type asteroid with a silicate surface composition.
Photometric observations made in 2010 at the Organ Mesa Observatory at Las Cruces, New Mexico, and the Hunters Hill Observatory at Ngunnawal, Australian Capital Territory, give a synodic rotation period of 23.740 ± 0.001 hours. The bimodal light curve shows a maximum brightness variation of 0.45 ± 0.03 in magnitude.
Measurements made with the IRAS observatory give a diameter of 91.58 ± 4.14 km and a geometric albedo of 0.19 ± 0.02. By comparison, the MIPS photometer on the Spitzer Space Telescope gives a diameter of 88.30 ± 8.51 km and a geometric albedo of 0.20 ± 0.04. When the asteroid was observed occulting a star, the results showed a diameter of 89.1 ± 1.1 km.