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/