                        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 27

                               South of Orion
                   Image Credit & Copyright: Vikas Chander

   Explanation: South of the large star-forming region known as the Orion
   Nebula, lies bright blue reflection nebula NGC 1999. At the edge of the
   Orion molecular cloud complex some 1,500 light-years distant, NGC
   1999's illumination is provided by the embedded variable star V380
   Orionis. The nebula is marked with a dark sideways T-shape at center
   right in this telescopic vista that spans about two full moons on the
   sky. Its dark shape was once assumed to be an obscuring dust cloud seen
   in silhouette. But infrared data suggest the shape is likely a hole
   blown through the nebula itself by energetic young stars. In fact, this
   region abounds with energetic young stars producing jets and outflows
   with luminous shock waves. Cataloged as Herbig-Haro (HH) objects, named
   for astronomers George Herbig and Guillermo Haro, the shocks have
   intense reddish hues. HH1 and HH2 are just below and right of NGC 1999.
   HH222, also known as the Waterfall nebula, looks like a red gash near
   top right in the frame. To create the shocks stellar jets push through
   the surrounding material at speeds of hundreds of kilometers per
   second.

                 Tomorrow's picture: the western eastern sea
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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