An afterglow is a broad high arch of whitish or rosy light appearing in the sky due to very fine particles of dust suspended in the high regions of the atmosphere. An afterglow may appear above the highest clouds in the hour of deepening twilight, or reflected from the high snowfields in mountain regions long after sunset. The particles produce a scattering effect upon the component parts of white light. (From Wikipedia)
Afterglow is not an imaginary color to Colorpedia but an unsustainable color to it. Afterglow ranges from red to orange and sometimes may involve blue to purple too. Therefore, quite a lot of results might be found if afterglow is named as color.
Sunset in Lamma Island, Hong Kong after an eruption took place in Mount Pinatubo in 1991