Editing 243 Ida (section)

== Orbit and rotation ==
[[File:Ida orbit.svg|thumb|Orbit and positions of Ida and five planets as of 9 March 2009]]
Ida is a member of the [[Koronis family]] of [[asteroid belt|asteroid-belt]] asteroids.<ref name="Chapman1996p700" /> Ida orbits the Sun at an average distance of {{convert|2.862|AU|Gm|abbr=on}}, between the orbits of [[Mars]] and [[Jupiter]].<ref name="Holm1994" /><ref name="JPL2008" /> Ida takes 4.84089 years to complete one orbit.<ref name="JPL2008" />

Ida rotates in the [[retrograde motion|retrograde direction]] with a [[rotation period]] of 4.63 hours (roughly 5 hours).<ref name="VokrouhlickyNesvornyBottke2003p147">{{harvnb|Vokrouhlicky|Nesvorny|Bottke|2003|p=147}}</ref><ref name="GeisslerPetitGreenberg1996p58" /><ref name="Archinal2018"/> The calculated maximum [[moment of inertia]] of a uniformly dense object the same shape as Ida coincides with the spin axis of the asteroid. This suggests that there are no major variations of density within the asteroid.<ref name="ThomasProckter2004" /> Ida's axis of rotation [[precession#Astronomy|precesses]] with a period of 77 thousand years, due to the gravity of the Sun acting upon the nonspherical shape of the asteroid.<ref name="Slivan1995p134">{{harvnb|Slivan|1995|p=134}}</ref>