In November 2007, a rotational lightcurve of Arne was obtained from photometric observations by Robert Stephens at GMARS (G79) and Santana observatories (646) in California. Analysis gave a bimodal lightcurve with an exceptionally long rotation period of 123.7±0.1 hours and a brightness amplitude of 0.24±0.05magnitude (U=3−).[9][10] The results supersede an incorrect period of 8.60 hours from a noisy lightcurve taken by Larry E. Robinson at Sunflower Observatory (739) in Kansas in November 2001 (U=1).[12]
Diameter and albedo
According to the surveys carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), the Japanese Akari satellite, and the Infrared Astronomical Satellite IRAS, Arne measures 45.176±0.350, 53.09±0.75 and 57.42±1.5 kilometers in diameter, and its surface has an albedo of 0.0446±0.002, 0.054±0.002 and 0.067±0.004, respectively.[6][7][8]
Other published measurements by the WISE team also includes mean-diameters of 46.687±0.665 km51.539±0.547 km, 52.57±13.47 km and 61.45±20.10 km with corresponding albedos of 0.067±0.004, 0.0553±0.0301, 0.03±0.05 and 0.03±0.02.[5][9] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0258 and a diameter of 57.20 km based on an absolute magnitude of 10.8.[9] An asteroid occultation on 3 February 2015, gave a best-fit ellipse dimension of 53.0 × 53.0 kilometers.[5] These timed observations are taken when the asteroid passes in front of a distant star. However the quality of the measurements are poorly rated.[5]
^ 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.