1947 Iso-Heikkilä

1947 Iso-Heikkilä, provisional designation, is a carbonaceous Eos 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 Turku Observatory in Southwest Finland. It was named after the location of the discovering observatory, which is also known as the "Iso-Heikkilä Observatory".

Orbit and classification
Iso-Heikkilä is a member of the Eos family (606), the largest asteroid family in the outer main belt consisting of nearly 10,000 asteroids. It orbits the Sun in the outer main-belt 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.

Physical characteristics
The C-type asteroid has been characterized as a rare and reddish D-type asteroid by Pan-STARRS' large-scale photometric survey.

Diameter and albedo
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 0.0571 and a diameter of 29.2 kilometers with an absolute magnitude of 11.4.

Rotation period
In October 2005, a rotational lightcurve 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 lightcurve is ambiguous and several alternative period solutions are possible (U=n.a.)

Naming
This minor planet was named for the farm, which is 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 (Iso-Heikkilän tähtitorni). It was the observatory's first minor planet discovery. The official naming citation was published by the Minor Planet Center on 1 August 1980 (M.P.C. 5450).