Configuration and gradual dynamics of prominence-related X-ray coronal cavities

X-ray images of the solar corona obtained by the S-054 telescope on Skylab have been analyzed together with H-alpha filtergrams from the Catania Astrophysical Observatory and EUV and magnetic data, to study the morphology and the evolution of the coronal structures associated with prominences (coronal cavities). Prominences associated with young (up to three solar rotations) and old (greater than eight) magnetic neutral lines are significantly less stable than those associated with middle-aged neutral lines. Downward bending of the top of the inner magnetic loop, necessary in some models of prominences, is not detected in these X-ray observations. The relevance of these results to models of prominence formation is discussed.