hours and a high brightness variation of magnitude (). At the same time, Alexander Kurtenkov at Sofia University, and a team of Bulgarian students obtained a concurring period of hours with an amplitude of magnitude (). In July 2017, French and Swiss astronomers René Roy and Raoul Behrend confirmed the period measuring a nearly identical rotation of () hours and an amplitude of magnitude (). Poles Two lightcurves, published in 2016, using modeled photometric data from the Lowell Photometric Database (LPD) and other sources, gave a concurring sidereal period of () and () hours, respectively. Each modeled lightcurve also determined two spin axes of (93.0°, −71.0°) and (277.0°, −35.0°), as well as (56.0°, −78.0°) and (255.0°, −57.0°) in ecliptic coordinates (λ, β), respectively. Diameter and albedo American photometrist Frederick Pilcher also determined a diameter of kilometers based on a visual absolute magnitude of , and an albedo of 0.057 derived from its measured V–R color index (see above). The Collaborative Asteroid Lightcurve Link adopts Pilcher's albedo of 0.057 and derives a diameter of 19.57 kilometers. Notes References External links Lightcurve Database Query (LCDB), at www.minorplanet.info Dictionary of Minor Planet Names, Google books Asteroids and comets rotation curves, CdR – Geneva Observatory, Raoul Behrend Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center 000682 Discoveries by August Kopff Named minor planets 19090617 Hagar