1026 Ingrid is a stony Florian asteroid and a long-lost minor planet from the inner regions of the asteroid belt, approximately 7 kilometers in diameter. It was discovered on 13 August 1923 by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in southwest Germany. Its provisional designation was 1923 NY.
The asteroid was observed for only a few days after its discovery and subsequently became a lost minor planet for nearly 63 years. It was recovered in 1986 by Japanese astronomer Syuichi Nakano, who identified that it had been observed and provisionally designated several times during its lost period (as 1957 UC, 1963 GD, 1981 WL8, and 1986 ES2). With its recovery, the list of long-lost numbered asteroids was reduced to four.
Orbit and classification: 1026 Ingrid is a member of the Flora family (402), the largest family of stony asteroids. It orbits the Sun in the inner main-belt at a distance of 1.8–2.7 AU once every 3 years and 5 months (1,237 days). Its orbit has an eccentricity of 0.18 and an inclination of 5° with respect to the ecliptic.
Physical characteristics: The asteroid is an assumed S-type (stony) asteroid. Its rotation period is approximately 5 hours. Measurements from the Akari satellite and NEOWISE surveys indicate a diameter between 5.73 and 7.67 kilometers, with a surface albedo ranging from 0.144 to 0.43.
Naming: The minor planet was named after Ingrid, the niece and godchild of German astronomer Albrecht Kahrstedt (1897–1971), who requested the naming in a personal letter to the discoverer in February 1926. Kahrstedt was also honored with the naming of asteroid 1587 Kahrstedt.
