                        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.

                              2022 February 18

                          Three Clusters in Puppis
                    Image Credit & Copyright: Dave Doctor

   Explanation: Galactic or open star clusters are young. The swarms of
   stars are born together near the plane of the Milky Way, but their
   numbers steadily dwindle as cluster members are ejected by galactic
   tides and gravitational interactions. Caught in this telescopic frame
   over three degrees across are three good examples of galactic star
   clusters, seen toward the southern sky's nautical constellation Puppis.
   Below and left, M46 is some 5,500 light-years in the distance. Right of
   center M47 is only 1,600 light-years away and NGC 2423 (top) is about
   2500 light-years distant. Around 300 million years young M46 contains a
   few hundred stars in a region about 30 light-years across. Sharp eyes
   can spot a planetary nebula, NGC 2438, at about 11 o'clock against the
   M46 cluster stars. But that nebula's central star is billions of years
   old, and NGC 2438 is likely a foreground object only by chance along
   the line of sight to youthful M46. Even younger, aged around 80 million
   years, M47 is a smaller and looser star cluster spanning about 10
   light-years. Star cluster NGC 2423 is pushing about 750 million years
   in age though. NGC 2423 is known to harbor an extrasolar planet,
   detected orbiting one of its red giant stars.

                    Tomorrow's picture: mammals in space
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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