value	quality	siderealorsynodic	author	ref	method
21.0530	2	Synodic	Waszczak	2015AJ....150...75W	Lightcurve
21.0691	2	Synodic	Pal	2020ApJS..247...26P	Lightcurve
21.0774	2	Sidereal	Durech	2020A&A...643A..59D	Model
21.0890	3-	Synodic	Mazzone	2014MPBu...41...17M	Lightcurve