A faint ray-like feature in the Sun’s corona that extends radially outwards from coronal holes at the Sun’s poles; also referred to as a polar plume. Coronal plumes can be seen at the Sun’s limb in visible light with coronagraphs and during eclipses, as well as at X-ray and ultraviolet wavelengths. The bases of the plumes originate in patches of bright emission in coronal holes. Plumes have been traced out to at least fifteen solar radii on images from the SOHO spacecraft. Plumes are usually denser and cooler than their surroundings, and are most easily identified during solar minimum when coronal holes are clearly seen at the poles of the Sun. There is as yet no conclusive evidence for plumes in equatorial coronal holes, although there is no known reason why they should not also occur at lower latitudes.