¿ 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. 2020 July 21 [2]See Explanation. Clicking on the picture will download the highest resolution version available. Iron in the Butterfly Nebula Image Credit: [3]NASA, [4]ESA, [5]Hubble; Processing & [6]License: [7]Judy Schmidt Explanation: Can stars, like caterpillars, transform themselves into butterflies? No, but in the case of the [8]Butterfly Nebula -- it sure looks like it. Though its wingspan covers over 3 [9]light-years and its estimated surface temperature exceeds 200,000 degrees, [10]C, the dying central star of NGC 6302, the featured [11]planetary nebula, has become exceptionally hot, shining brightly in [12]visible and [13]ultraviolet light but hidden from direct view by a dense torus of dust. [14]This sharp close-up was recorded by the [15]Hubble Space Telescope and is reprocessed here to show off the remarkable details of the complex [16]planetary nebula, highlighting in particular light emitted by [17]iron, shown in red. [18]NGC 6302 lies about 4,000 light-years away in the [19]arachnologically correct constellation of the Scorpion ([20]Scorpius). [21]Planetary nebulas evolve from outer atmospheres of [22]stars like our [23]Sun, but usually fade in about 20,000 years. Great Debates in Astronomy: [24]2020: How will humanity first discover extraterrestrial life? Tomorrow's picture: open space __________________________________________________________________ [25]< | [26]Archive | [27]Submissions | [28]Index | [29]Search | [30]Calendar | [31]RSS | [32]Education | [33]About APOD | [34]Discuss | [35]> __________________________________________________________________ Authors & editors: [36]Robert Nemiroff ([37]MTU) & [38]Jerry Bonnell ([39]UMCP) NASA Official: Phillip Newman [40]Specific rights apply. [41]NASA Web Privacy Policy and Important Notices A service of: [42]ASD at [43]NASA / [44]GSFC & [45]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2007/Butterfly_HubbleSchmidt_4767.jpg 3. https://www.nasa.gov/ 4. https://www.esa.int/ 5. https://hla.stsci.edu/ 6. https://creativecommons.org/licenses/by/2.0/ 7. https://geckzilla.com/ 8. https://en.wikipedia.org/wiki/Butterfly 9. https://exoplanets.nasa.gov/faq/26/what-is-a-light-year/ 10. https://en.wikipedia.org/wiki/Celsius 11. https://www.nasa.gov/mission_pages/chandra/multimedia/planetary_nebula.html 12. https://science.nasa.gov/ems/09_visiblelight 13. https://science.nasa.gov/ems/10_ultravioletwaves 14. https://www.flickr.com/photos/geckzilla/50023499248/ 15. https://www.nasa.gov/mission_pages/hubble/story/index.html 16. https://apod.nasa.gov/apod/ap190929.html 17. https://periodic.lanl.gov/26.shtml 18. https://en.wikipedia.org/wiki/NGC_6302 19. https://en.wikipedia.org/wiki/Arachnid 20. http://hawastsoc.org/deepsky/sco/index.html 21. https://en.wikipedia.org/wiki/Planetary_nebula 22. https://science.nasa.gov/astrophysics/focus-areas/how-do-stars-form-and-evolve 23. https://apod.nasa.gov/apod/ap190526.html 24. https://apod.nasa.gov/debate/debate100th.html 25. https://apod.nasa.gov/apod/ap200720.html 26. https://apod.nasa.gov/apod/archivepix.html 27. https://apod.nasa.gov/apod/lib/apsubmit2015.html 28. https://apod.nasa.gov/apod/lib/aptree.html 29. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 30. https://apod.nasa.gov/apod/calendar/allyears.html 31. https://apod.nasa.gov/apod.rss 32. https://apod.nasa.gov/apod/lib/edlinks.html 33. https://apod.nasa.gov/apod/lib/about_apod.html 34. http://asterisk.apod.com/discuss_apod.php?date=200721 35. https://apod.nasa.gov/apod/ap200722.html 36. http://www.phy.mtu.edu/faculty/Nemiroff.html 37. http://www.phy.mtu.edu/ 38. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 39. http://www.astro.umd.edu/ 40. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 41. https://www.nasa.gov/about/highlights/HP_Privacy.html 42. https://astrophysics.gsfc.nasa.gov/ 43. https://www.nasa.gov/ 44. https://www.nasa.gov/centers/goddard/ 45. http://www.mtu.edu/