Discovered by Y. Väisälä MPC designation 1947 Iso-Heikkilä Minor planet category main-belt · (outer) Discovered 4 March 1935 Discoverer Yrjö Väisälä | Discovery date 4 March 1935 Alternative names 1935 EA Observation arc 81.69 yr (29,836 days) Orbits Sun Named after Iso-Heikkilä (location) Asteroid group Asteroid belt | |
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1947 Iso-Heikkilä, provisional designation 1935 EA, is a carbonaceous asteroid from the outer region of the asteroid belt, approximately 30 kilometers in diameter. It was discovered on 4 March 1935, by Finnish astronomer Yrjö Väisälä at Iso-Heikkilä Observatory in Southwest Finland.
Iso-Heikkilä orbits the Sun at a distance of 3.0–3.3 AU once every 5 years and 7 months (2,046 days). Its orbit has an eccentricity of 0.04 and an inclination of 12° with respect to the ecliptic. As no precoveries were taken, and no prior identifications were made, the body's observation arc begins with its discovery observation.
The C-type asteroid is also classified as a rare and reddish D-type by Pan-STARRS' large-scale survey. According to the surveys carried out by the Japanese Akari satellite and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Iso-Heikkilä measures 30.7 and 31.6 kilometers in diameter, and its surface has an albedo of 0.091 and 0.049, respectively. The Collaborative Asteroid Lightcurve Link derives an albedo of 0.057 and a diameter of 29.2 kilometers based on an absolute magnitude of 11.4.
In October 2005, a rotational light-curve of Iso-Heikkilä was obtained from photometric observations by Slovak astronomer Adrián Galád. It gave a rotation period of 5.0158 hours with a brightness variation of 0.35 magnitude. However, the light-curve is ambiguous and several alternative period solutions are possible (U=n.a.)
It is named for the farm, located in the Iso-Heikkilä district and owned by Turku University. It became the site of the Turku Observatory, which is also called Iso-Heikkilä Observatory (Finnish: Iso-Heikkilän tähtitorni). It was the observatory's first minor planet discovery. Naming citation was published on 1 August 1980 (M.P.C. 5450).