[1] Astronomer Federico Manzini obtained a provisional lightcurve of Dagmar from photometric observations in March 2004.
It gave a tentative rotation period of 12 hours with a brightness variation of 0.15 magnitude (U=1).
[1] According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Dagmar measures between 35.78 and 45.194 kilometers in diameter, and its surface has an albedo between 0.035 and 0.057.
[4][5][7][8] The Collaborative Asteroid Lightcurve Link adopts the results obtained by 17 observations made by IRAS, that is an albedo of 0.0565 and a diameter of 35.78 kilometers with an absolute magnitude of 10.97.
[2] The official naming citation was published by the Minor Planet Center on 15 December 1968 (M.P.C.