1266 Tone/ˈtoʊni/ is a dark background asteroid from the outer regions of the asteroid belt, approximately 80 kilometers in diameter. Discovered by astronomer Okuro Oikawa at the Tokyo Observatory in 1927,[14] it was assigned the provisional designation 1927 BD. The asteroid was later named after the Tone River, one of Japan's largest rivers.[2]
The body's observation arc begins with its identification as 1933 BM at the German Heidelberg Observatory in January 1933, or four years after its official discovery observation at Tokyo.[14]
In October 1999, two rotational lightcurves of Tone were obtained from photometric observations by American astronomer Brian Warner at his Palmer Divide Observatory (716) in Colorado. Lightcurve analysis gave two divergent rotation periods of 7.40 and 11.82 hours with a brightness variation of 0.06 and 0.12 magnitude, respectively (U=2/2).[11][12][a] Observation by Italian astronomers Roberto Crippa and Federico Manzini in October 2005, gave another tentative period of 12.9 hours and an amplitude of 0.07 magnitude (U=2-).[13] The LCDB currently adopts a period of 7.40 hours.[3]
The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.0566 and a diameter of 73.34 kilometers based on an absolute magnitude of 9.41.[3]
^ 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)