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 October 8 [2]See Explanation. Clicking on the picture will download the highest resolution version available. Two Comets in Southern Skies Image Credit & [3]Copyright: [4]Jose J. Chambo ([5]Cometografia) Explanation: Heading for its closest approach to the Sun or perihelion on December 20, comet [6]C/2017 K2 (PanSTARRS) remains a sight for telescopic observers as it sweeps through planet Earth's southern hemisphere skies. [7]First time visitor from the [8]remote Oort cloud this comet PanSTARRS [9]sports a greenish coma and whitish dust tail about half a degree long at the upper left in a deep image from September 21. It also shares the starry field of view toward the constellation Scorpius with another comet, [10]73P/Schwassmann-Wachmann 3, seen about 1 degree [11]below and right of PanSTARRS. Astronomers estimate that first time visitor comet [12]C/2017 K2 (PanSTARRS) has been inbound from the Oort cloud for some 3 million years along a hyperbolic orbit. Schwassmann-Wachmann 3 is more familiar [13]though. The periodic comet loops through its own elliptical orbit, from just beyond the orbit of Jupiter to the vicinity of Earth's orbit, once every 5.4 years. Just passing in the night, this comet PanSTARRS is about 20 light-minutes from Earth in the [14]September 21 image. Seen to be disintegrating since 1995, [15]Schwassmann-Wachmann 3 was about 7.8 light-minutes away. Tomorrow's picture: northern skylights __________________________________________________________________ [16]< | [17]Archive | [18]Submissions | [19]Index | [20]Search | [21]Calendar | [22]RSS | [23]Education | [24]About APOD | [25]Discuss | [26]> __________________________________________________________________ Authors & editors: [27]Robert Nemiroff ([28]MTU) & [29]Jerry Bonnell ([30]UMCP) NASA Official: Phillip Newman [31]Specific rights apply. [32]NASA Web Privacy Policy and Important Notices A service of: [33]ASD at [34]NASA / [35]GSFC, [36]NASA Science Activation & [37]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2210/2017K2_2022-09-21_media.jpg 3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 4. http://cometografia.es/acerca-de/contactar/ 5. http://cometografia.es/ 6. https://earthsky.org/astronomy-essentials/large-comet-c-2017-k2-panstarrs-summer-2022/ 7. https://hubblesite.org/contents/news-releases/2017/news-2017-40.html 8. https://solarsystem.nasa.gov/solar-system/oort-cloud/overview/ 9. https://apod.nasa.gov/apod/ap220721.html 10. https://en.wikipedia.org/wiki/73P/Schwassmann–Wachmann 11. https://apod.nasa.gov/apod/image/2210/2017K2_2022-09-21_web-label.jpg 12. https://en.wikipedia.org/wiki/C/2017_K2_(PanSTARRS) 13. https://apod.nasa.gov/apod/ap220604.html 14. https://cometografia.es/2017k2-panstarrs-73p-schwassmann-wachmann-2022-09-21/ 15. https://apod.nasa.gov/apod/ap060513.html 16. https://apod.nasa.gov/apod/ap221007.html 17. https://apod.nasa.gov/apod/archivepix.html 18. https://apod.nasa.gov/apod/lib/apsubmit2015.html 19. https://apod.nasa.gov/apod/lib/aptree.html 20. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 21. https://apod.nasa.gov/apod/calendar/allyears.html 22. https://apod.nasa.gov/apod.rss 23. https://apod.nasa.gov/apod/lib/edlinks.html 24. https://apod.nasa.gov/apod/lib/about_apod.html 25. http://asterisk.apod.com/discuss_apod.php?date=221008 26. https://apod.nasa.gov/apod/ap221009.html 27. http://www.phy.mtu.edu/faculty/Nemiroff.html 28. http://www.phy.mtu.edu/ 29. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 30. http://www.astro.umd.edu/ 31. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 32. https://www.nasa.gov/about/highlights/HP_Privacy.html 33. https://astrophysics.gsfc.nasa.gov/ 34. https://www.nasa.gov/ 35. https://www.nasa.gov/centers/goddard/ 36. https://science.nasa.gov/learners 37. http://www.mtu.edu/