Discovered by T. Urata MPC designation 2090 Mizuho Discovered 12 March 1978 Orbits Sun Discovery site JCPM Yakiimo Station | Discovery date 12 March 1978 Minor planet category main-belt · (outer) Absolute magnitude 10.99 Discoverer Takeshi Urata Asteroid group Asteroid belt | |
Named after Mizuho Urata
(daughter of discoverer) Alternative names 1978 EA · 1937 RE
1942 PG · 1951 EH
1952 HA4 · 1953 RT
1953 TP · 1959 VD
1964 TE · 1970 WV
1978 EJ People also search for 2091 Sampo, 2089 Cetacea | ||
2090 Mizuho, provisional designation 1978 EA, is a stony asteroid from the outer region of the asteroid belt, approximately 18 kilometers in diameter. It was discovered by Japanese astronomer Takeshi Urata at the JCPM Yakiimo Station in Shimizu, Japan on 12 March 1978.
The S-type asteroid orbits the Sun at a distance of 2.7–3.5 AU once every 5 years and 5 months (1,968 days). Its orbit has an eccentricity of 0.13 and an inclination of 12° with respect to the ecliptic. The first used observation was obtained at Heidelberg Observatory in 1951, extending the Mizuho's observation arc by 27 years prior to its official discovery observation.
In February 2010, a rotational light-curve for Mizuho was obtained from photometric observations by James W. Brinsfield at the Via Capote Observatory in California. It gave a rotation period of 5.47 hours with a brightness variation of 0.30 magnitude (U=2+).
According to the surveys carried out by the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Mizuho measures between 18.0 and 18.9 kilometers in diameter and its surface has an albedo of between 0.207 and 0.219, which is typical for stony asteroids. The Collaborative Asteroid Lightcurve Link, however assumes a standard albedo for a carbonaceous C-type asteroid of 0.057 and correspondingly calculates a much larger diameter of 35.3 kilometers.
The discoverer named the minor planet after his daughter, Mizuho Urata. It was the first asteroid in over 50 years to be discovered by a non-professional astronomer, which set off a wave of interest in amateur asteroid discovery, especially in Japan. Naming citation was published before November 1977 (M.P.C. 4482).