value quality siderealorsynodic author ref method 6.3373 2 Sidereal Durech 2018A&A...617A..57D Model 6.3373 2 Sidereal Martikainen 2021A&A...649A..98M Model 6.3376 2 Synodic Pal 2020ApJS..247...26P Lightcurve