1845 Helewalda
1845 Helewalda is a carbonaceous Eoan asteroid in the outer regions of the asteroid belt, approximately 20 kilometers in diameter. It was discovered by Swiss astronomer Paul Wild at Zimmerwald Observatory near Bern, Switzerland, on 30 October 1972. The asteroid was named after Helen Gachnang, a friend of the discoverer.
Orbit and classification
Helewalda 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 2.8–3.1 AU once every 5 years and 1 month. Its orbit has an eccentricity of 0.06 and an inclination of 11° with respect to the ecliptic. The first precovery was taken at Lowell Observatory in 1931, extending the asteroid's observation arc by 41 years prior to its discovery.Physical characteristics
Helewalda is an assumed carbonaceous C-type asteroid.Rotation period
Based on observations made by French astronomer René Roy in March 2010, Helewalda has a well-determined rotation period of hours with a brightness variation of 0.26 in magnitude.Between 2009 and 2015, other lightcurves were obtained at the Oakley Southern Sky Observatory in Australia, the Via Capote Observatory at Thousand Oaks, California, and the Palomar Transient Factory at Palomar Observatory. They gave a similar period of, and hours with a corresponding amplitude of 0.20, 0.28 and 0.15, respectively.