Orchis is a non-family asteroid of the main belt's background population.[5] It orbits the Sun in the inner asteroid belt at a distance of 1.8–3.0 AU once every 3 years and 9 months (1,374 days; semi-major axis of 2.42 AU). Its orbit has an eccentricity of 0.26 and an inclination of 5° with respect to the ecliptic.[1] The asteroid was first observed as A906 BH at Heidelberg in January 1906. The body's observation arc begins with its official discovery observation in August 1927.[18]
Due to his many discoveries, Karl Reinmuth submitted a large list of 66 newly named asteroids in the early 1930s. The list covered his discoveries with numbers between (1009) and (1200). This list also contained a sequence of 28 asteroids, starting with 1054 Forsytia, that were all named after plants, in particular flowering plants(also see list of minor planets named after animals and plants).[19]
In 2010, three rotational lightcurves of Orchis were obtained from photometric observations. Lightcurve analysis gave a rotation period of 16.061, 16.075 and 16.1 hours with a brightness amplitude of between 0.23 and 0.31 magnitude (U=2+/2/3).[13][15][16] A modeled lightcurve based on optical data from a large collaboration network found a concurring period of 16.0657 hours and two spin axis of (255.0°, 27.0°) and (71.0°, 28.0°) in ecliptic coordinates (λ, β).[14]
Diameter and albedo
According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Orchis measures between 20.755 and 24.62 kilometers in diameter and its surface has an albedo between 0.029 and 0.051.[6][7][8][9][10][11][12] The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.0430 and a diameter of 23.28 kilometers based on an absolute magnitude of 12.2.[4][10]
^ abcdUsui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. (online, AcuA catalog p. 153)