1335 Demoulina is a stony asteroid belonging to the Flora family of the inner asteroid belt. It was discovered on 7 September 1934 by German astronomer Karl Reinmuth at the Heidelberg‑Königstuhl State Observatory in southwest Germany. An independent observation was made by Belgian astronomer Eugène Delporte at the Uccle Observatory on 13 September 1934, but the Minor Planet Center credits Reinmuth as the sole discoverer.
Orbit and classification
Demoulina orbits the Sun at a semi‑major axis of approximately 2.24 AU, with an orbital period of 3.35 years (about 1 225 days). Its orbit has an eccentricity of 0.154 and an inclination of 2.55° relative to the ecliptic. The asteroid is classified as a member of the Flora family, a large collisional group of S‑type asteroids located in the inner main belt.
Physical characteristics
The asteroid is estimated to be roughly 7 kilometres in diameter. Measurements from infrared surveys give a mean diameter between 7.0 and 7.7 km, and a geometric albedo ranging from about 0.20 to 0.26, consistent with an S‑type (silicaceous) composition. Photometric observations indicate a slow rotation period; the most reliable determinations give a synodic rotation period of 74.86 ± 0.10 hours (approximately 3.12 days), which is considerably longer than the typical rotation periods of similarly sized main‑belt asteroids.
Naming
The asteroid was named “Demoulina” in honour of Professor Demoulin, a Belgian astronomer affiliated with Ghent University. The citation for the name appears in the official Minor Planet Circulars.
Observation history
The observation arc for 1335 Demoulina spans over 82 years, providing a well‑determined orbit with an uncertainty parameter of 0. Its absolute magnitude (H) is recorded at 12.8–13.9, reflecting its modest size and relatively high albedo.
Overall, 1335 Demoulina is a typical inner‑belt Flora family asteroid, notable for its slow rotation and the dedication of its name to a Belgian scholar.
