This file is in the public domain because it was created by NASA and ESA. NASA Hubble material (and ESA Hubble material prior to 2009) is copyright-free and may be freely used as in the public domain without fee, on the condition that only NASA, STScI, and/or ESA is credited as the source of the material. This license does not apply if ESA material created after 2008 or source material from other organizations is in use.
HST image of the Cotton Candy Nebula. Credits: Sun Kwok and Kate Su (University of Calgary), Bruce Hrivnak (Valparaiso University), and NASA. http://hubblesite.org/gallery/album/nebula_collection/pr1998011f/