                        Astronomy Picture of the Day

    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.

                                 2024 July 6

                          NGC 7789: Caroline's Rose
                 Image Credit & Copyright: Massimo Di Fusco

   Explanation: Found among the rich starfields of the Milky Way, star
   cluster NGC 7789 lies about 8,000 light-years away toward the
   constellation Cassiopeia. A late 18th century deep sky discovery of
   astronomer Caroline Lucretia Herschel, the cluster is also known as
   Caroline's Rose. Its visual appearance in small telescopes, created by
   the cluster's complex of stars and voids, is suggestive of nested rose
   petals. Now estimated to be 1.6 billion years young, the galactic or
   open cluster of stars also shows its age. All the stars in the cluster
   were likely born at the same time, but the brighter and more massive
   ones have more rapidly exhausted the hydrogen fuel in their cores.
   These have evolved from main sequence stars like the Sun into the many
   red giant stars shown with a yellowish cast in this color composite.
   Using measured color and brightness, astronomers can model the mass and
   hence the age of the cluster stars just starting to "turn off" the main
   sequence and become red giants. Over 50 light-years across, Caroline's
   Rose spans about half a degree (the angular size of the Moon) near the
   center of the sharp telescopic image.

                      Tomorrow's picture: cloudy skies
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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