[8] In August 2013, a rotational lightcurve of Hagar was obtained from nine nights of photometric observations by Frederick Pilcher at the Organ Mesa Observatory (G50) in Arizona.

Analysis gave a well-defined, classically shaped bimodal lightcurve with a rotation period of (4.8503±0.0001) hours and a high brightness variation of 0.52±0.03 magnitude (U=3).

[8][a] At the same time, Alexander Kurtenkov at Sofia University, and a team of Bulgarian students obtained a concurring period of 4.854±0.011 hours with an amplitude of 0.49±0.03 magnitude (U=3).

[13] In July 2017, French and Swiss astronomers René Roy and Raoul Behrend confirmed the period measuring a nearly identical rotation of (4.8516±0.0003) hours and an amplitude of 0.51±0.02 magnitude (U=3).

[15][16] American photometrist Frederick Pilcher also determined a diameter of 19±4 kilometers based on a visual absolute magnitude of 12.27±0.07, and an albedo of 0.057 derived from its measured V–R color index (see above).