Daniel du Toit (Harvard College Observatory, Boyden station, Bloemfontein, South Africa) discovered this comet on 1945 December 11.05 in Triangulum Australe. He estimated the magnitude as 7. Du Toit obtained only four additional observations on December 12.05, 13.07, 14.07, and 15.07.
During the first week of 1946 January, L. E. Cunningham (Aberdeen, Maryland) used the five observations obtained by du Toit and computed a parabolic orbit with a perihelion date of 1945 December 28.012 and a perihelion distance of 0.006305 AU. Two additional orbits, were given which represented the likely limits. Cunningham said the comet might have been "a brilliant, naked-eye object within a couple of degrees of the sun" on the day of perihelion, but his hope that the comet might have been detected by coronagraphs either before or after its occultation by the sun, never panned out. In addition, nothing was located along Cunningham's search ephemerides during January 1946. In particular, Enrique Gaviola (Córdoba Observatory) said bad weather prevented any observations from being made in Argentina during 1946 January. Fred Whipple pointed out that Cunningham's orbit was very similar to comets 1668, 1843 I, 1880 I, 1882 II, and 1887 I.
B. G. Marsden has written two papers investigating the sungrazing comets. During 1967 he used four of the positions obtained between 1945 December 11 and 15, and computed a parabolic orbit with a perihelion date of December 27.9652, and a perihelion distance of 0.007516 AU. During 1989 he computed some alternative orbital solutions and remarked on the similarity to the orbits of the sungrazers C/1882 R1 and C/1965 S1. He concluded that it was likely that comet du Toit was produced, along with these two comets, by the breakup of a comet during the 12th century. This comet may have been comet X/1106 C1.