26 Proserpina is a main-belt asteroid discovered by R. Luther on May 5, 1853. It is named after the Roman goddess Proserpina, the daughter of Ceres and the Queen of the Underworld.
Photometric observations of this asteroid have produced discrepant estimates of the rotation period. A period of 12.13 hours was reported in 1979, followed by 10.6 hours in 1981 and 6.67 hours in 2001. Observations made in 2007 at the Oakley Observatory in Terre Haute, Indiana produced a light curve with a period of 13.06 ± 0.03 hours and a brightness variation of 0.21 ± 0.01 in magnitude. This was refined by a 2008 study, giving a period of 13.110 ± 0.001 hours.