In June 2015, a rotational lightcurve of Anneliese was obtained from photometric observations by Uruguayan astronomer Eduardo Álvarez at the Los Algarrobos Observatory (I38). Lightcurve analysis gave a well-defined rotation period of 11.2863±0.0002 hours with a brightness variation of 0.16±0.02magnitude, indicative of a spherical, non-elongated shape (U=3). At the time Anneliese was one of only 17 three-digit numbered asteroids for which no period was published.[10] In May 2015, Julian Oey at the Blue Mountains Observatory (Q68), Australia, determined a concurring period of 11.294±0.002 hours with an amplitude of 0.55±0.03 magnitude (U=2+).[11] In May 2015 a collaboration of Spanish amateur astronomers including Alfonso Garceràn (J08), Amadeo Macias (Z95), Enrique Mansego (J67), Pedro Rodriguez (Z98) and Juan de Haro (I57) measured a period of 5.63±0.01 hours—or half the period solution of the other observations, with an amplitude of 0.13±0.01 magnitude (U=2+).[12]
Diameter and albedo
According to the survey 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, Anneliese measures (47.07±4.5), (48.590±0.216) and (48.85±0.57) kilometers in diameter and its surface has an albedo of (0.0605±0.013), (0.057±0.013) and (0.057±0.002), respectively.[7][8][9] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0505 and a diameter of 46.98 kilometers based on an absolute magnitude of 10.5,[13] while Alvares gives a diameter of (46.3±3.5 km) and an albedo of (0.06±0.02).[10] An asteroid occultation, observed on 14 September 2012, gave a best-fit ellipse dimension of 48.0 × 48.0 kilometers.[6] These timed observations are taken when the asteroid passes in front of a distant star. However the quality of the measurement is rated poorly.[6]
Further published mean-diameters by the WISE team include (43.35±0.30 km), (45.974±14.40 km) and (50.756±0.905 km) with corresponding albedos of (0.04±0.01), (0.0586±0.0483) and (0.0308±0.0014).[6][13]
^ abcMasiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121.