value	quality	siderealorsynodic	author	ref	method
21.2920	2	Sidereal	Durech	2023A&A...675A..24D	Model
21.3010	2	Synodic	Waszczak	2015AJ....150...75W	Lightcurve
21.3106	2	Synodic	Pal	2020ApJS..247...26P	Lightcurve