| Minorplanet: | yes |
| 1947 Iso-Heikkilä | |
| Background: |
|
| Discovered: | 4 March 1935 |
| Mpc Name: | (1947) Iso-Heikkilä |
| Alt Names: | 1935 EA |
| Epoch: | 4 September 2017 (JD 2458000.5) |
| Uncertainty: | 0 |
| Observation Arc: | 81.94 yr (29,928 days) |
| Perihelion: | 3.0367 AU |
| Semimajor: | 3.1539 AU |
| Eccentricity: | 0.0372 |
| Period: | 5.60 yr (2,046 days) |
| Mean Motion: | / day |
| Inclination: | 11.912° |
| Asc Node: | 90.908° |
| Arg Peri: | 144.06° |
| Dimensions: | 29.20 km km km |
| Albedo: | 0.0571 |
| Abs Magnitude: | 10.8011.411.51 |
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".
Iso-Heikkilä is a member of the Eos family, 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.
The C-type asteroid has been characterized as a rare and reddish D-type asteroid by Pan-STARRS large-scale photometric 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 0.0571 and a diameter of 29.2 kilometers with an absolute magnitude of 11.4.
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
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 (Finnish: 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 .