Elliptical trajectory of a single planet around a star without perihelion advance [Trajectoire elliptique d'une unique planète autour d'une étoile sans avance de périhélie].
See some related pictures (possibly including this one):
(CMAP28 WWW site: this page was created on 02/07/2026 and last updated on 02/08/2026 14:51:39 -CET-)