保护地球，探索宇宙，发现文明
2023年12月24日 NGC 2440: Cocoon of a New White Dwarf Image Credit: NASA, ESA, Hubble; Processing: H. Bond (STScI), R. Ciardullo (PSU), Forrest Hamilton (STScI) Explanation: What’s that in the center? Like a butterfly, a white dwarf star begins its life by casting off a cocoon of gas that enclosed its former self. In this analogy, however, the Sun would be...
2022年5月21日 Planetary Nebula Abell 7 Image Credit & Copyright: Donald Waid, Ron Dilulio Explanation: Very faint planetary nebula Abell 7 is some 1,800 light-years distant, just south of Orion in planet Earth’s skies in the constellation Lepus, The Hare. Surrounded by Milky Way stars and near the line-of-sight to distant background galaxies, its gen...
2021年8月22日 Explosions from White Dwarf Star RS Oph Illustration Credit & Copyright: David A. Hardy & PPARC Explanation: Spectacular explosions keep occurring in the binary star system named RS Ophiuchi. Every 20 years or so, the red giant star dumps enough hydrogen gas onto its companion white dwarf star to set off a brilliant thermonuclear explosi...
2019 September 29 MyCn 18: The Engraved Hourglass Planetary Nebula Image Credit: NASA, ESA, Hubble; Processing & License: Judy Schmidt Explanation: Do you see the hourglass shape — or does it see you? If you can picture it, the rings of MyCn 18 trace the outline of an hourglass — although one with an unusual eye in its center. Either way, th...