value quality siderealorsynodic author ref method 19.8750 2 Synodic Waszczak 2015AJ....150...75W Lightcurve 19.9548 2 Sidereal Durech 2023A&A...675A..24D Model 20.0995 2 Synodic Pal 2020ApJS..247...26P Lightcurve