                        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 January 12

                    Comet Leonard Closeup from Australia
           Image Credit & Copyright: Blake Estes (itelescope.net)

   Explanation: What does Comet Leonard look like up close? Although we
   can't go there, imaging the comet's coma and inner tails through a
   small telescope gives us a good idea. As the name implies, the ion tail
   is made of ionized gas -- gas energized by ultraviolet light from the
   Sun and pushed outward by the solar wind. The solar wind is quite
   structured and sculpted by the Sun's complex and ever changing magnetic
   field. The effect of the variable solar wind combined with different
   gas jets venting from the comet's nucleus accounts for the tail's
   complex structure. Following the wind, structure in Comet Leonard's
   tail can be seen to move outward from the Sun even alter its wavy
   appearance over time. The blue color of the ion tail is dominated by
   recombining carbon monoxide molecules, while the green color of the
   coma surrounding the head of the comet is created mostly by a slight
   amount of recombining diatomic carbon molecules. Diatomic carbon is
   destroyed by sunlight in about 50 hours -- which is why its green glow
   does not make it far into the ion tail. The featured imagae was taken
   on January 2 from Siding Spring Observatory in Australia. Comet
   Leonard, presently best viewed from Earth's Southern Hemisphere, has
   rounded the Sun and is now headed out of the Solar System.

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

