Solar coronal streamers

The solar disk locations of 13 coronal streamers were determined from a combination of eclipse, K-coronameter (1 1/8r1 1/2 R ), and balloon-borne coronagraph (2<r<6 R ) observations taken during 1964 and 1965. Of this sample, three were observed twice on photographs taken over intervals of four and 28 days. Most of these streamers could be structurally associated with K-coronameter enhancements to establish their disk locations.Those features having known disk locations all lay above some stage of chromospheric disk activity in the form of active regions and prominences. The average lifetime of three K-coronameter streamer-enhancements, for which all or nearly all of their lifetimes were known, was about 4 solar rotations. Rotation rates for the lower latitude streamer-enhancements (30°) were essentially identical to the underlying surface. One high latitude feature ( 50°) which overlay a quiescent prominence had a rate equivalent to the surface rate at 30° latitude. In general those K-coronameter enhancements associated with streamers came into existence over time periods of 14 days and disappeared by gradually blending into the background coronal pattern. All the observed structures are explained by a model consisting of localized, high density features (streamers) which overlie disk activity and are imbedded in a uniform but weaker azimuthally-symmetric quiet corona.The National Center for Atmospheric Research is sponsored by the National Science Foundation.