The Tulip in the Swan . ... The complex and beautiful nebula is shown here in a composite image that maps emission from ionized sulfur, hydrogen, and oxygen atoms into red, green, and blue colors. Ultraviolet radiation from young, energetic O star HDE 227018 ionizes the atoms and powers the emission from the Tulip Nebula. HDE 227018, is the bright star very near the blue arc at image center. ... NASA Web Site Statements, Warnings, and Disclaimers . NASA Official: Jay Norris. ...