What is creating the strange texture of IC 418? Dubbed the Spirograph Nebula [ http://heritage.sts…] for its resemblance to drawings from a cyclical drawing tool [ http://www.wordsmit…], planetary nebula [ http://www.noao.edu…] IC 418 shows patterns [ http://mathworld.wo…] that are not well understood. Perhaps they are related to chaotic winds [ http://www-spof.gsf…] from the variable central star, which changes brightness unpredictably [ http://adsabs.harva…] in just a few hours. By contrast, evidence indicates that only a few million years ago, IC 418 [ http://www.skyhound…] was probably a well-understood star similar to our Sun [ http://www.seds.org…]. Only a few thousand years ago, IC 418 was probably a common red giant [ http://www.historyo…] star. Since running out of nuclear fuel [ http://csep10.phys.…], though, the outer envelope has begun expanding outward leaving a hot remnant core destined to become a white-dwarf star [ http://imagine.gsfc…], visible in the image [ http://heritage.sts…] center. The light from the central core excites surrounding atoms [ http://www.pbs.org/…] in the nebula [ http://antwrp.gsfc.…] causing them to glow. IC 418 lies about 2000 light-years [ http://chandra.harv…] away and spans 0.3 light-years across. This recently released false-color image [ http://heritage.sts…] taken from the Hubble Space Telescope [ http://www.stsci.ed…] reveals the unusual details.
Explanation
What is creating the strange texture of IC 418? Dubbed the Spirograph Nebula [ http://heritage.sts…] for its resemblance to drawings from a cyclical drawing tool [ http://www.wordsmit…], planetary nebula [ http://www.noao.edu…] IC 418 shows patterns [ http://mathworld.wo…] that are not well understood. Perhaps they are related to chaotic winds [ http://www-spof.gsf…] from the variable central star, which changes brightness unpredictably [ http://adsabs.harva…] in just a few hours. By contrast, evidence indicates that only a few million years ago, IC 418 [ http://www.skyhound…] was probably a well-understood star similar to our Sun [ http://www.seds.org…]. Only a few thousand years ago, IC 418 was probably a common red giant [ http://www.historyo…] star. Since running out of nuclear fuel [ http://csep10.phys.…], though, the outer envelope has begun expanding outward leaving a hot remnant core destined to become a white-dwarf star [ http://imagine.gsfc…], visible in the image [ http://heritage.sts…] center. The light from the central core excites surrounding atoms [ http://www.pbs.org/…] in the nebula [ http://antwrp.gsfc.…] causing them to glow. IC 418 lies about 2000 light-years [ http://chandra.harv…] away and spans 0.3 light-years across. This recently released false-color image [ http://heritage.sts…] taken from the Hubble Space Telescope [ http://www.stsci.ed…] reveals the unusual details.
