value quality siderealorsynodic author ref method 6.8429 3 Synodic Higgins 2006MPBu...33...64H Lightcurve 6.8431 2 Sidereal Durech 2016A&A...587A..48D Model 6.8431 2 Sidereal Hanus 2016A&A...586A.108H Model