755 Quintilla
755 Quintilla ("prov. designation:" "or" ) is a metallic background asteroid from the outer regions of the asteroid belt, approximately in diameter. It was discovered on 6 April 1908, by American astronomer Joel Metcalf at the Taunton Observatory in Massachusetts, United States. For its size, the M-type asteroid has a relatively short rotation period of 4.55 hours. It was named "Quintilla", an Italian female first name, for no reason other than being the first asteroid name beginning with the letter . Orbit and classification. "Quintilla" is a non-family asteroid of the main belt's background population when applying  the hierarchical clustering method to its proper orbital elements. It orbits the Sun in the outer asteroid belt at a distance of 2.7–3.6 AU once every 5 years and 8 months (2,073 days; semi-major axis of 3.18 AU). Its orbit has an eccentricity of 0.14 and an inclination of 3° with respect to the ecliptic. The body's observation arc begins at Vienna Observatory on 1 September 1915, almost 7 years after its official discovery observation by Joel Metcalf at Taunton. Naming. This minor planet was named "Quintilla", a name of an Italian first name, that was proposed  by Arville D. Walker, secretary to the American astronomer and director of Harvard Observatory Harlow Shapley (1885–1972), as no other asteroid name began with the letter when it was named in 1926. The was mentioned in "The Names of the Minor Planets" by Paul Herget in 1955 (). Physical characteristics. In the Tholen classification, "Quintilla" is a metallic M-type asteroid. Rotation period. Several rotational lightcurves of "Quintilla" were obtained from photometric observations. Analysis of the best-rated lightcurves by Robert K. Buchheim and Donald Pray (2004), Laurent Bernasconi, Reiner Stoss, Petra Korlević, Maja Hren, Aleksandar Cikota, Ljuban Jerosimic, and Raoul  Behrend (2005), as well as Joseph Masiero (2006), gave a well-defined rotation period of (), () and () hours with a brightness variation of (), () and () magnitude, respectively (). In November 2018, Michael and Matthew Fauerbach obtained a period of () hours and an amplitude of () magnitude (). Diameter and albedo. According to the surveys carried out by the Japanese Akari satellite, the Infrared Astronomical Satellite IRAS, and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), "Quintilla" measures (), () and () kilometers in diameter and its surface has an albedo of (), () and (), respectively. Alternative mean-diameter measurements published by the WISE team include () and  () with corresponding albedos of () and (). The "Collaborative Asteroid Lightcurve Link" derives an albedo of 0.1781 and a diameter of 36.16 kilometers based on an absolute magnitude of 9.7.