Sieböhme orbits the Sun in the central main-belt at a distance of 2.3–3.0 AU once every 4 years and 4 months (1,581 days). Its orbit has an eccentricity of 0.14 and an inclination of 6° with respect to the ecliptic.[1] In 1907, the body was first identified as A917 SO at the Crimean Simeis Observatory, extending its observation arc by 34 years prior to its official discovery observation.[13]
Physical characteristics
In August 2012, two rotational lightcurves of Sieböhme were obtained at the Palomar Transient Factory in California, and by Italian astronomer Albino Carbognani. These lightcurves gave a rotation period of 56.8129 and 56.81 hours with a brightness variation of 0.44 and 0.45 magnitude, respectively (U=2/2).[10][11] One month later, photometric observations by amateur astronomer Pierre Antonini gave a period of 56.65 hours and an amplitude of 0.47 magnitude (U=2).[9] As most minor planets rotate within 2 to 20 hours around their axis, Sieböhme has a relatively long period, despite not being a slow rotator.
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Sieböhme measures between 25.16 and 29.38 kilometers in diameter, and its surface has an albedo between 0.043 and 0.064.[4][5][6][7][8] The Collaborative Asteroid Lightcurve Link (CALL) derives an albedo of 0.0477 and a diameter of 26.56 kilometers with an absolute magnitude of 11.80. Although CALL derives an albedo that is darker than that of a carbonaceous asteroid, it classifies Sieböhme as a stony asteroid.[3]
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