Editing 243 Ida (section)

== Origin ==
Ida originated in the breakup of the roughly {{convert|120|km|mi|abbr=on|sigfig=2}} diameter Koronis parent body.<ref name="VokrouhlickyNesvornyBottke2003p147" /> The progenitor asteroid had partially differentiated, with heavier metals migrating to the core.<ref name="GreenbergBottkeNolanGeissler1996p117">{{harvnb|Greenberg|Bottke|Nolan|Geissler|1996|p=117}}</ref> Ida carried away insignificant amounts of this core material.<ref name="GreenbergBottkeNolanGeissler1996p117" /> It is uncertain how long ago the disruption event occurred. According to an analysis of Ida's cratering processes, its surface is more than a billion years old.<ref name="GreenbergBottkeNolanGeissler1996p117" /> However, this is inconsistent with the estimated age of the Ida–Dactyl system of less than 100&nbsp;million years;<ref name="HurfordGreenberg2000p1595">{{harvnb|Hurford|Greenberg|2000|p=1595}}</ref> it is unlikely that Dactyl, due to its small size, could have escaped being destroyed in a major collision for longer. The difference in age estimates may be explained by an increased rate of cratering from the debris of the Koronis parent body's destruction.<ref name="CarrollOstlie1996p878">{{harvnb|Carroll|Ostlie|1996|p=878}}</ref>