NGC 2392: Double-Shelled Planetary Nebula
To some, this huge nebula resembles a person's head surrounded by a parka hood . In 1787, astronomer William Herschel discovered this unusual planetary nebula: NGC 2392 . More recently, the Hubble Space Telescope imaged the nebula in visible light , The featured image of the nebula shows gas clouds so complex they are not fully understood . NGC 2392 is a double-shelled planetary nebula , with the more distant gas having composed the outer layers of a Sun -like star only 10,000 years ago. The outer shell contains unusual light-year long orange filaments. The inner filaments visible are being ejected by strong wind of particles from the central star. The NGC 2392 Nebula spans about 1/3 of a light year and lies in our Milky Way Galaxy , about 3,000 light years distant, toward the constellation of the Twins ( Gemini ).