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 November 22
    [2]The featured image shows two clusters of blue stars placed next to
    each other. Please see the explanation for more detailed information.

                      A Double Star Cluster in Perseus
                  Image Credit & Copyright: [3]Tommy Lease

   Explanation: Few star clusters this close to each other. Visible to the
   unaided eye from [4]dark sky areas, it was cataloged in [5]130 BC by
   Greek astronomer [6]Hipparchus. Some 7,000 light-years away, [7]this
   pair of [8]open star clusters is also an easy binocular target, a
   [9]striking starfield in the [10]northern constellation of the mythical
   Greek hero [11]Perseus. Now known as [12]h and chi Persei, or NGC 869
   (above right) and [13]NGC 884, the clusters themselves are separated by
   only a few hundred [14]light-years and contain stars much younger and
   hotter than the [15]Sun. In addition to being physically close
   together, [16]the clusters' ages [17]based on their individual stars
   are similar - evidence that both [18]clusters were likely a product of
   the same [19]star-forming region.

                       Tomorrow's picture: open space
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    Authors & editors: [31]Robert Nemiroff ([32]MTU) & [33]Jerry Bonnell
                                 ([34]UMCP)
          NASA Official: Phillip Newman [35]Specific rights apply.
              [36]NASA Web Privacy Policy and Important Notices
                A service of: [37]ASD at [38]NASA / [39]GSFC,
                         [40]NASA Science Activation
                           & [41]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2211/DoubleCluster_Lease_3756.jpg
   3. https://www.instagram.com/colorado_astro/
   4. https://apod.nasa.gov/apod/ap200408.html
   5. https://en.wikipedia.org/wiki/130_BC
   6. https://en.wikipedia.org/wiki/Hipparchus
   7. https://www.instagram.com/p/CkYcGXJOmPg/
   8. https://en.wikipedia.org/wiki/Open_cluster
   9. https://www.intermountainpet.com/hubfs/Blog_Images/Dogs-tilting-their-heads.jpg
  10. https://en.wikipedia.org/wiki/Perseus_(constellation)
  11. https://en.wikipedia.org/wiki/Perseus
  12. http://www.messier.seds.org/xtra/ngc/n0869.html
  13. https://en.wikipedia.org/wiki/NGC_884
  14. https://spaceplace.nasa.gov/light-year/en/
  15. https://solarsystem.nasa.gov/solar-system/sun/in-depth/
  16. https://apod.nasa.gov/apod/ap201118.html
  17. https://ui.adsabs.harvard.edu/abs/2001AJ....122..248K/abstract
  18. http://asterisk.apod.com/viewtopic.php?f=24&t=18009
  19. https://science.nasa.gov/astrophysics/focus-areas/how-do-stars-form-and-evolve
  20. https://apod.nasa.gov/apod/ap221121.html
  21. https://apod.nasa.gov/apod/archivepix.html
  22. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  23. https://apod.nasa.gov/apod/lib/aptree.html
  24. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  25. https://apod.nasa.gov/apod/calendar/allyears.html
  26. https://apod.nasa.gov/apod.rss
  27. https://apod.nasa.gov/apod/lib/edlinks.html
  28. https://apod.nasa.gov/apod/lib/about_apod.html
  29. http://asterisk.apod.com/discuss_apod.php?date=221122
  30. https://apod.nasa.gov/apod/ap221123.html
  31. http://www.phy.mtu.edu/faculty/Nemiroff.html
  32. http://www.phy.mtu.edu/
  33. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  34. http://www.astro.umd.edu/
  35. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  36. https://www.nasa.gov/about/highlights/HP_Privacy.html
  37. https://astrophysics.gsfc.nasa.gov/
  38. https://www.nasa.gov/
  39. https://www.nasa.gov/centers/goddard/
  40. https://science.nasa.gov/learners
  41. http://www.mtu.edu/