Discovered by Norman Robert Pogson Minor planet category Main belt Aphelion 446.706 Gm (2.986 AU) Discovered 23 May 1856 Spectral type S-type asteroid Named after Isis | Discovery date May 23, 1856 Adjectives Isidian Perihelion 283.890 Gm (1.898 AU) Orbits Sun Discoverer N. R. Pogson Discovery site Radcliffe Observatory | |
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Similar N R Pogson discoveries, Other celestial objects | ||
42 Isis /ˈaɪsᵻs/ is a large main-belt asteroid, measuring 100.2 km in diameter. It was discovered by N.R. Pogson on May 23, 1856, at Oxford. It was Pogson's first asteroid discovery.
The asteroid's name was chosen by Manuel John Johnson, director of the Radcliffe Observatory in Oxford. Although Isis is the name of an Egyptian goddess, the name was chosen in homage to Pogson's astronomer daughter, (Elizabeth) Isis Pogson. In addition, the Isis is the stretch of the River Thames that runs through Oxford.
The light curve inversion technique, when applied to photometric observations of this asteroid, show multiple local irregularities. The overall shape displays little elongation, with a ratio between the major and minor axes equal to 1.1. The measured rotation period for this model is 13.59701 hours. The spectrum of 42 Isis reveals the strong presence of the mineral Olivine, a relatively rarity in the asteroid belt.