period was confirmed by Gérald Rousseau in March 2012, who determined a very similar period of hours with an amplitude of magnitude (). Diameter and albedo According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), and the Japanese Akari satellite, Annika measures (), () and () kilometers in diameter and its surface has an albedo of (), () and (), respectively. The Collaborative Asteroid Lightcurve Link derives an albedo of 0.2062 and a diameter of 22.20 kilometers based on an absolute magnitude of 10.6. Alternative mean-diameter measurements published by the WISE team include (), (), () and () with corresponding albedos of (), (), () and (). On 26 August 2010, an asteroid occultation of Annika gave a best-fit ellipse dimension of (). These timed observations are taken when the asteroid passes in front of a distant star. However, these two observations have received a poor quality rating. References External links Lightcurve Database Query (LCDB), at www.minorplanet.info Dictionary of Minor Planet Names, Google books Asteroids and comets rotation curves, CdR – Geneva Observatory, Raoul Behrend Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center 000817 Discoveries by Max Wolf Named minor planets 000817 19160206