936 Kunigunde


936 Kunigunde is a dark Themistian asteroid from the outer regions of the asteroid belt, approximately in diameter. It was discovered on 8 September 1920, by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory. The carbonaceous B-type asteroid has a rotation period of 9.4 hours. It was named "Kunigunde", a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanac Lahrer Hinkender Bote.

Orbit and classification

Kunigunde is a core member of the Themis family, when applying the hierarchical clustering method to its proper orbital elements. The very large family of carbonaceous asteroids is named after 24 Themis. Kunigunde orbits the Sun in the outer main-belt at a distance of 2.6–3.7 AU once every 5 years and 6 months. Its orbit has an eccentricity of 0.18 and an inclination of 2° with respect to the ecliptic. The asteroid was first observed as at Simeiz Observatory on 27 April 1913. The body's observation arc begins at Heidelberg with its official discovery observation on 8 September 1920.

Naming

This minor planet was named "Kunigunde", after a female name picked from the Lahrer Hinkender Bote, published in Lahr, southern Germany. A Hinkender Bote was a very popular almanac, especially in the alemannic-speaking region from the late 17th throughout the early 20th century. The calendar section contains feast days, the dates of important fairs and astronomical ephemerides. For 3 March, the calendar gives "Kunigund" as the German name day analogue next to Kunigunde and Titian, the protestant and catholic entries in the calendar of saints, likely referring to Cunigunde of Luxembourg and Titian of Brescia.

Reinmuth's ''calendar names''

As with 22 other asteroids – starting with 913 Otila, and ending with 1144 Oda – Reinmuth selected names from this calendar due to his many asteroid discoveries that he had trouble thinking of proper names. These names are not related to the discoverer's contemporaries. Lutz Schmadel, the author of the Dictionary of Minor Planet Names learned about Reinmuth's source of inspiration from private communications with Dutch astronomer Ingrid van Houten-Groeneveld, who worked as a young astronomer at Heidelberg.

Physical characteristics

In both the Tholen- and SMASS-like taxonomy of the Small Solar System Objects Spectroscopic Survey, Kunigunde is a B-type asteroid, a somewhat brighter spectral type than the common C-type typical for Themistian asteroids.

Rotation period and poles

In March 2018, a rotational lightcurve of Kunigunde was obtained from photometric observations by French amateur astronomer René Roy. Lightcurve analysis gave a well-defined rotation period of hours with a brightness variation of magnitude. Richard Ditteon at the Oakley Southern Sky Observatory determined a period of with an amplitude of magnitude. Photometry by Angeli and Guimarães at observatories in Brazil and Argentina gave a similar period of hours. In 2013, an international study modeled a lightcurve with a sidereal period of 8.82653 hours and found two spin axes at and in ecliptic coordinates .

Diameter and albedo

According to the survey carried out by the Japanese Akari satellite, the Infrared Astronomical Satellite IRAS, and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Kunigunde measures, and kilometers in diameter and its surface has an albedo of, and, respectively.
The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0792 and a diameter of 39.29 km based on an absolute magnitude of 10.4. Further published mean-diameters and albedos by the WISE team include and with corresponding albedos of and. An asteroid occultation on 21 November 2004, gave a best-fit ellipse dimension of 39.0 × 39.0 kilometers. These timed observations are taken when the asteroid passes in front of a distant star. However the quality of the measurement is poorly rated.