Chronology of the formation process of Venusian novae and the associated coronae

Abstract

Venusian radial features (novae) have been interpreted to represent the initial stage of the corona evolution. Thus they are hypothesized to be older than the corona rim structure. However, based on recent studies, the majority of novae that are located in the inner part of the coronae seem to postdate corona formation. The topography, as well as the mutual age relationships of coexisting coronae and novae, indicates that nova formation may have taken place during different corona evolution phases. In this study we present a chronology for nova formation that offers an explanation of both age and location relations of the novae inside the coronae. Due to the proven age differences between coronae and novae located within them, we conceive most of the novae within the corona annulus as representations of reactivation of the corona location. We believe that the morphology, the topography, and the age relations of corona annulus and nova radial features depend on the stage of corona evolution during the reactivation period or event, when the nova is formed. Our model explains the observed regularity between nova location and age relations of the corona-nova joint structure better than the assumed movement of the lithosphere or migrating mantle plumes.