10252 Heidigraf

10252 Heidigraf, provisional designation 4164 T-1, is a Koronian asteroid from the outer regions of the asteroid belt, approximately 6 kilometers (3.7 miles) in diameter. It was discovered during the Palomar–Leiden Trojan survey on 26 March 1971, by Ingrid and Cornelis van Houten at Leiden, and Tom Gehrels at Palomar Observatory in California, United States. The likely elongated S-type asteroid has a brightness variation of 0.56 magnitude. It was named after Heidi Graf, a former Head of the ESTEC Communications Office.

Orbit and classification

Heidigraf is a core member of the Koronis family (605), a very large outer asteroid family of six thousand known members with nearly co-planar ecliptical orbits. It orbits the Sun in the outer main-belt at a distance of 2.7–3.1 AU once every 4 years and 10 months (1,760 days; semi-major axis of 2.85 AU). Its orbit has an eccentricity of 0.07 and an inclination of 2° with respect to the ecliptic. The body's observation arc begins at Palomar on 24 March 1971, two nights prior to its official discovery observation.

Palomar–Leiden Trojan survey

The survey designation "T-1" stands for the first Palomar–Leiden Trojan survey, named after the fruitful collaboration of the Palomar and Leiden Observatory in the 1960s and 1970s. Gehrels used Palomar's Samuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped the photographic plates to Ingrid and Cornelis van Houten at Leiden Observatory where astrometry was carried out.