¿

                        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 February 7
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                Blue Straggler Stars in Globular Cluster M53
                    Image Credit: [3]ESA/Hubble, [4]NASA

   Explanation: If our Sun were part of this star cluster, the [5]night
   sky would glow like a jewel box of bright stars. This cluster, known as
   [6]M53 and cataloged as NGC 5024, is one of about 250 [7]globular
   clusters that survive in our Galaxy. Most of the stars in [8]M53 are
   older and redder than our Sun, but some enigmatic stars appear to be
   bluer and younger. These young [9]stars might contradict the hypothesis
   that all the stars in [10]M53 formed at nearly the same time. These
   unusual stars are known as [11]blue stragglers and are unusually common
   in M53. After much debate, [12]blue stragglers are now thought to be
   stars rejuvenated by fresh matter falling in from a binary star
   companion. By [13]analyzing pictures of globular clusters like the
   [14]featured image taken by the Hubble Space Telescope, astronomers
   [15]use the abundance of stars like [16]blue stragglers to help
   determine the age of the globular cluster and hence a [17]limit on the
   age of the universe. [18]M53, visible with a binoculars towards the
   [19]constellation of Bernice's Hair (Coma Berenices), contains over
   250,000 stars and is one of the furthest [20]globulars from the center
   of our Galaxy.

                      Tomorrow's picture: ripple stars
     __________________________________________________________________

      [21]< | [22]Archive | [23]Submissions | [24]Index | [25]Search |
   [26]Calendar | [27]RSS | [28]Education | [29]About APOD | [30]Discuss |
                                    [31]>
     __________________________________________________________________

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

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2102/m53_hubble_4131.jpg
   3. https://www.spacetelescope.org/
   4. https://www.nasa.gov/
   5. https://en.wikipedia.org/wiki/Nightfall_(Asimov_short_story_and_novel)
   6. https://en.wikipedia.org/wiki/Messier_53
   7. https://apod.nasa.gov/apod/globular_clusters.html
   8. http://gclusters.altervista.org/cluster_4.php?ggc=M+53
   9. http://asterisk.apod.com/viewtopic.php?f=24&t=18009
  10. https://www.nasa.gov/feature/goddard/2017/messier-53
  11. http://www.solstation.com/x-objects/bluestrag.htm
  12. https://astronomy.swin.edu.au/cosmos/b/blue+stragglers
  13. https://ui.adsabs.harvard.edu/abs/1999AJ....118..453C/abstract
  14. https://esahubble.org/images/potw1140a/
  15. https://en.wikipedia.org/wiki/Blue_straggler
  16. https://apod.nasa.gov/apod/ap971104.html
  17. http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question28.html
  18. https://www.messier-objects.com/messier-53/
  19. http://www.ianridpath.com/startales/comaberenices.htm
  20. https://en.wikipedia.org/wiki/Globular_clusters
  21. https://apod.nasa.gov/apod/ap210206.html
  22. https://apod.nasa.gov/apod/archivepix.html
  23. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  24. https://apod.nasa.gov/apod/lib/aptree.html
  25. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  26. https://apod.nasa.gov/apod/calendar/allyears.html
  27. https://apod.nasa.gov/apod.rss
  28. https://apod.nasa.gov/apod/lib/edlinks.html
  29. https://apod.nasa.gov/apod/lib/about_apod.html
  30. http://asterisk.apod.com/discuss_apod.php?date=210207
  31. https://apod.nasa.gov/apod/ap210208.html
  32. http://www.phy.mtu.edu/faculty/Nemiroff.html
  33. http://www.phy.mtu.edu/
  34. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  35. http://www.astro.umd.edu/
  36. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  37. https://www.nasa.gov/about/highlights/HP_Privacy.html
  38. https://astrophysics.gsfc.nasa.gov/
  39. https://www.nasa.gov/
  40. https://www.nasa.gov/centers/goddard/
  41. http://www.mtu.edu/