1020 Arcadia, provisional designation 1924 QV, is a stony Agnia asteroid from the central regions of the asteroid belt, approximately 11 kilometers (7 miles) in diameter. It was discovered on 7 March 1924, by German astronomer Karl Reinmuth at the Heidelberg Observatory in Heidelberg, Germany.[1] The asteroid was named after the Greek region of Arcadia.[3]
Orbit and classification
Arcadia is a member of the Agnia family (514),[5][6] a very large family of stony asteroids with more than 2000 known members.[13] They most likely formed from the breakup of a basalt object, which in turn was spawned from a larger parent body that underwent igneous differentiation.[6] The family's parent body and namesake is the asteroid 847 Agnia.[13]
It orbits the Sun in the central main-belt at a distance of 2.7–2.9 AU once every 4 years and 8 months (1,703 days; semi-major axis of 2.79 AU). Its orbit has an eccentricity of 0.04 and an inclination of 4° with respect to the ecliptic.[4] The body's observation arc begins at Heidelberg in March 1924, six days after its official discovery observation.[1]
In November 2011, a fragmentary rotational lightcurve of Arcadia was obtained from photometric observations by Gordon Gartrelle at the University of North Dakota. Lightcurve analysis gave a rotation period of 17.02 hours with a brightness amplitude of 0.05 magnitude (U=1).[11] As of 2018, no secure period has been obtained.[10]
Diameter and albedo
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Arcadia measures between 10.067 and 13.02 kilometers in diameter and its surface has an albedo between 0.150 and 0.2364.[7][8][9] The Collaborative Asteroid Lightcurve Link assumes an albedo 0.057, i.e. an albedo for a carbonaceous rather than for a stony asteroid, and consequently calculates a much larger diameter of 21.16 kilometers based on an absolute magnitude of 12.1.[10] It may be speculated whether this anomaly is a glitch in the data base.