1656 Suomi
1656 Suomi is a binary Hungaria asteroid and sizable Mars-crosser from the innermost regions of the asteroid belt. It was discovered on 11 March 1942, by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland, who named it "Suomi", the native name of Finland. The stony asteroid has a short rotation period of 2.6 hours and measures approximately 7.9 kilometers in diameter. In June 2020, a companion was discovered by Brian Warner, Robert Stephens and Alan Harris. The satellite measures more than 1.98 kilometers in diameter, about 26% of the primary, which it orbits once every 57.9 hours at an average distance of 30 kilometers.
Orbit and classification
Suomi is a member of the Hungaria family, which form the innermost dense concentration of asteroids in the Solar System. It orbits the Sun at a distance of 1.6–2.1 AU once every 2 years and 7 months. Its orbit has an eccentricity of 0.12 and an inclination of 25° with respect to the ecliptic.It is also classified as a Mars-crossing asteroid, since its perihelion – the point in its orbit, where it is nearest to the Sun – is less than the average orbital distance of the planet Mars. Suomis observation arc begins on the preceding night of its discovery, with an observation taken at Johannesburg Observatory on 10 March 1942.