M2 9: Wings of a Butterfly Nebula . ... WFPC2 , HST , NASA Explanation: Are stars better appreciated for their art after they die? ... The expended gas frequently forms an impressive display called a planetary nebula that fades gradually over thousand of years. M2-9 , a butterfly planetary nebula 2100 light-years away shown in representative colors, has wings that tell a strange but incomplete tale . In the center, two stars orbit inside a gaseous disk 10 times the orbit of Pluto . ...