¿ 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. 2021 March 8 [2]See Explanation. Moving the cursor over the image will bring up an annotated version. Clicking on the picture will download the highest resolution version available. Three Tails of Comet NEOWISE Image Credit & Copyright: [3]Nicolas Lefaudeux Explanation: What created the unusual red tail in Comet NEOWISE? [4]Sodium. A spectacular sight back in the summer of 2020, Comet NEOWISE, at times, displayed something more than just a [5]surprisingly [6]striated [7]white dust tail and a [8]pleasingly patchy blue [9]ion tail. Some color sensitive images showed an unusual red tail, and [10]analysis showed much of this third tail's color was emitted by sodium. Gas rich in sodium atoms might have been liberated from [11]Comet NEOWISE's warming nucleus in early July by bright sunlight, electrically charged by [12]ultraviolet sunlight, and then pushed out by the [13]solar wind. The [14]featured image was captured in mid-July from [15]Brittany, [16]France and shows the real colors. [17]Sodium comet tails have been seen before but are [18]rare -- this one disappeared by late July. [19]Comet C/2020 F3 (NEOWISE) has [20]since faded, lost all of its bright tails, and now approaches the orbit of [21]Jupiter as it heads back to the outer [22]Solar System, to return only in about 7,000 years. Astrophysicists: [23]Browse 2,400+ codes in the Astrophysics Source Code Library Tomorrow's picture: mars 360 __________________________________________________________________ [24]< | [25]Archive | [26]Submissions | [27]Index | [28]Search | [29]Calendar | [30]RSS | [31]Education | [32]About APOD | [33]Discuss | [34]> __________________________________________________________________ Authors & editors: [35]Robert Nemiroff ([36]MTU) & [37]Jerry Bonnell ([38]UMCP) NASA Official: Phillip Newman [39]Specific rights apply. [40]NASA Web Privacy Policy and Important Notices A service of: [41]ASD at [42]NASA / [43]GSFC & [44]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2103/Neowise3Tails_Lefaudeux_1088.jpg 3. https://hdr-astrophotography.com/a-propos/ 4. https://youtu.be/dmcfsEEogxs?t=49 5. https://apod.nasa.gov/apod/ap200722.html 6. https://link.springer.com/article/10.1007/BF00644193 7. https://apod.nasa.gov/apod/ap200722.html 8. https://i.redd.it/58if334dkzm31.jpg 9. https://en.wikipedia.org/wiki/Comet_tail 10. https://ui.adsabs.harvard.edu/abs/2020DPS....5211102Y/abstract 11. https://apod.nasa.gov/apod/ap200812.html 12. https://science.nasa.gov/ems/10_ultravioletwaves 13. https://solarsystem.nasa.gov/resources/2288/the-solar-wind-across-our-solar-system/ 14. https://hdr-astrophotography.com/ 15. https://youtu.be/IG4H6gS3SNk 16. https://en.wikipedia.org/wiki/France 17. https://astronomy.swin.edu.au/cosmos/c/Cometary+Neutral+Tail 18. https://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=300913 19. https://en.wikipedia.org/wiki/Comet_NEOWISE 20. https://theskylive.com/c2020f3-info 21. https://solarsystem.nasa.gov/planets/jupiter/overview/ 22. https://solarsystem.nasa.gov/solar-system/our-solar-system/in-depth/ 23. http://ascl.net/ 24. https://apod.nasa.gov/apod/ap210307.html 25. https://apod.nasa.gov/apod/archivepix.html 26. https://apod.nasa.gov/apod/lib/apsubmit2015.html 27. https://apod.nasa.gov/apod/lib/aptree.html 28. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 29. https://apod.nasa.gov/apod/calendar/allyears.html 30. https://apod.nasa.gov/apod.rss 31. https://apod.nasa.gov/apod/lib/edlinks.html 32. https://apod.nasa.gov/apod/lib/about_apod.html 33. http://asterisk.apod.com/discuss_apod.php?date=210308 34. https://apod.nasa.gov/apod/ap210309.html 35. http://www.phy.mtu.edu/faculty/Nemiroff.html 36. http://www.phy.mtu.edu/ 37. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 38. http://www.astro.umd.edu/ 39. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 40. https://www.nasa.gov/about/highlights/HP_Privacy.html 41. https://astrophysics.gsfc.nasa.gov/ 42. https://www.nasa.gov/ 43. https://www.nasa.gov/centers/goddard/ 44. http://www.mtu.edu/