Astronomy Picture of the Day [1]Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2022 August 3 [2]The featured image shows a wide field image of the Cat's Eye nebula showing it to be surrounded by a large halo with many vertexes. Please see the explanation for more detailed information. Halo of the Cat's Eye Image Credit & Copyright: [3]Bray Falls Explanation: What created the unusual halo around the Cat's Eye nebula? No one is sure. What is sure is that the [4]Cat's Eye Nebula (NGC 6543) is one of the best known [5]planetary nebulae on the sky. Although haunting symmetries are seen in the bright [6]central region, this image was taken to feature its intricately structured outer halo, which spans over three [7]light-years across. [8]Planetary nebulae have long been appreciated as a final phase [9]in the life of a Sun-like star. Only recently however, have some planetaries been [10]found to have expansive halos, likely formed from material shrugged off during earlier [11]puzzling episodes in the [12]star's evolution. While the [13]planetary nebula phase is [14]thought to last for around 10,000 years, astronomers estimate the age of the [15]outer filamentary portions of the [16]Cat's Eye Nebula's halo to be 50,000 to 90,000 years. Tomorrow's picture: herculean stars __________________________________________________________________ [17]< | [18]Archive | [19]Submissions | [20]Index | [21]Search | [22]Calendar | [23]RSS | [24]Education | [25]About APOD | [26]Discuss | [27]> __________________________________________________________________ Authors & editors: [28]Robert Nemiroff ([29]MTU) & [30]Jerry Bonnell ([31]UMCP) NASA Official: Phillip Newman [32]Specific rights apply. [33]NASA Web Privacy Policy and Important Notices A service of: [34]ASD at [35]NASA / [36]GSFC, [37]NASA Science Activation & [38]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2208/CatsHalo_Falls_2719.jpg 3. https://www.instagram.com/astrofalls/ 4. https://apod.nasa.gov/apod/ap220710.html 5. https://en.wikipedia.org/wiki/Planetary_nebula 6. https://apod.nasa.gov/apod/ap211107.html 7. https://chandra.harvard.edu/photo/cosmic_distance.html 8. https://youtu.be/Mj06h8BeeOA 9. http://imagine.gsfc.nasa.gov/docs/teachers/lifecycles/stars.html 10. https://apod.nasa.gov/apod/ap140522.html 11. https://www.aanda.org/articles/aa/full_html/2018/12/aa33981-18/aa33981-18.html 12. https://science.nasa.gov/astrophysics/focus-areas/how-do-stars-form-and-evolve 13. https://astronomy.swin.edu.au/cosmos/p/Planetary+Nebulae 14. https://cdn.pixabay.com/photo/2019/09/04/08/24/cat-4451003_1280.jpg 15. https://youtu.be/tw0VJ1K93PM 16. https://en.wikipedia.org/wiki/Cat's_Eye_Nebula 17. https://apod.nasa.gov/apod/ap220802.html 18. https://apod.nasa.gov/apod/archivepix.html 19. https://apod.nasa.gov/apod/lib/apsubmit2015.html 20. https://apod.nasa.gov/apod/lib/aptree.html 21. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 22. https://apod.nasa.gov/apod/calendar/allyears.html 23. https://apod.nasa.gov/apod.rss 24. https://apod.nasa.gov/apod/lib/edlinks.html 25. https://apod.nasa.gov/apod/lib/about_apod.html 26. http://asterisk.apod.com/discuss_apod.php?date=220803 27. https://apod.nasa.gov/apod/ap220804.html 28. http://www.phy.mtu.edu/faculty/Nemiroff.html 29. http://www.phy.mtu.edu/ 30. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 31. http://www.astro.umd.edu/ 32. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 33. https://www.nasa.gov/about/highlights/HP_Privacy.html 34. https://astrophysics.gsfc.nasa.gov/ 35. https://www.nasa.gov/ 36. https://www.nasa.gov/centers/goddard/ 37. https://science.nasa.gov/learners 38. http://www.mtu.edu/