value quality siderealorsynodic author ref method 5.7791 2 Sidereal Durech 2018A&A...617A..57D Model 5.7791 2 Sidereal Durech 2019A&A...631A...2D Model 5.7800 2+ Synodic Krotz 2010MPBu...37...99K Lightcurve