NASAさんのインスタグラム写真 - (NASAInstagram)「We're celebrating 29 years since the launch of the @NASAHubble Space Telescope with a new look at the Southern Crab Nebula! See the nebula's hourglass structure ⏳, with bright edges like crab legs 🦀 ? The nebula is located several thousand light-years from Earth and appears to have two nested hourglass-shaped structures that were sculpted by a whirling pair of stars in a binary system. The duo consists of an aging red giant star and a burned-out star, a white dwarf. The red giant is shedding its outer layers. Some of this ejected material is attracted by the gravity of the companion white dwarf. The result is that both stars are embedded in a flat disk of gas stretching between them. This belt of material constricts the outflow of gas so that it only speeds away above and below the disk, forming what looks like an hourglass-shaped nebula. Credit: NASA/ESA/STScI #Hubble #29 #Crab #nebula #space #NASA #stars」4月25日 0時59分