"Rotraut" is a feminine German first name. This minor planet was likely named after the ballad Schön Rotraut (Pretty Rohtraut) by the German lyric poet Eduard Mörike (1804–1875). Lutz Schmadel, the author of the Dictionary of Minor Planet Names learned about Wolf's source of inspiration from private communications with Dutch astronomer Ingrid van Houten-Groeneveld, who worked as a young astronomer at Heidelberg.[2]
Two rotational lightcurves of Rotraut were obtained from photometric observations by Richard Ditteon at Oakley Southern Sky Observatory (E09), Australia, in February 2017, and by Tom Polakis at the Command Module Observatory (V02) in Arizona in May 2018. Lightcurve analysis gave an identical rotation period of 14.297 hours with a brightness variation of 0.25±0.05 and 0.29±0.03magnitude, respectively (U=3−/3−).[9][10] The result supersedes a tentative period determination of 14.586±0.003 hours and an amplitude of 0.24±0.01 magnitude by French amateur astronomers Stéphane Charbonnel and Claudine Rinner from July 2002 (U=2).[12]
In 2016, a modeled lightcurve gave a sidereal period of 14.3007±0.0002 hours using data from the Uppsala Asteroid Photometric Catalogue, the Palomar Transient Factory survey, and individual observers (such as above), as well as sparse-in-time photometry from the NOFS, the Catalina Sky Survey, and the La Palma surveys (950). The study also determined two spin axes of (201.0°, −41.0°) and (2.0°, −36.0°) in ecliptic coordinates (λ, β).[13]
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, Rotraut measures (56.47±5.5), (58.287±0.198) and (59.38±0.73) kilometers in diameter and its surface has an albedo of (0.0554±0.013), (0.054±0.004) and (0.051±0.002), respectively.[6][7][8] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0506 and a diameter of 56.42 kilometers based on an absolute magnitude of 10.1.[14] Alternative mean-diameter measurements published by the WISE team include (55.05±26.18 km), (58.70±0.56 km), (61.30±17.55 km) and (65.759±0.648 km) with corresponding albedos of (0.04±0.06), (0.047±0.006), (0.04±0.03) and (0.0409±0.0089).[5][14]
Three asteroid occultations, observed on 30 November 2009, 22 September 2013 and 21 November 2015, gave a best-fit ellipse dimension of (53.0 km × 53.0 km), (51.1 km × 37.7 km) (best), and (59.0 km × 59.0 km), respectively.[5] These timed observations are taken when the asteroid passes in front of a distant star. However the quality of the measurement is rated poorly.[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.
^ abcUsui, 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)
^Hanuš, J.; Ďurech, J.; Brož, M.; Marciniak, A.; Warner, B. D.; Pilcher, F.; et al. (March 2013). "Asteroids' physical models from combined dense and sparse photometry and scaling of the YORP effect by the observed obliquity distribution". Astronomy and Astrophysics. 551: A67. arXiv:1301.6943. Bibcode:2013A&A...551A..67H. ISSN0004-6361.