                        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.

                                2025 June 23
   A star field is shown in infrared light. In the center is an extremely
   complex nebula that is outlines an iconic heart. Glowing gas shades the
    center of the heart red. Please see the explanation for more detailed
                                information.

                        W5: Pillars of Star Formation
     Image Credit: NASA, WISE, IRSA; Processing & Copyright : Francesco
                                  Antonucci

   Explanation: How do stars form? Images of the star forming region W5
   like those in the infrared by NASA's Wide Field Infrared Survey
   Explorer (WISE, later NEOWISE) satellite provide clear clues with
   indications that massive stars near the center of empty cavities are
   older than stars near the edges. A likely reason for this is that the
   older stars in the center are actually triggering the formation of the
   younger edge stars. The triggered star formation occurs when hot
   outflowing gas compresses cooler gas into knots dense enough to
   gravitationally contract into stars. In the featured scientifically
   colored infrared image, spectacular pillars left slowly evaporating
   from the hot outflowing gas provide further visual clues. W5 is also
   known as Westerhout 5 (W5) and IC 1848. Together with IC 1805, the
   nebulas form a complex region of star formation popularly dubbed the
   Heart and Soul Nebulas. The featured image highlights a part of W5
   spanning about 2,000 light years that is rich in star forming pillars.
   W5 lies about 6,500 light years away toward the constellation of
   Cassiopeia.

   APOD Turns 30!: Free public lecture in Cork, Ireland tomorrow (Tuesday)
                                   at 7 pm
                      Tomorrow's picture: spiral spiral
     __________________________________________________________________

       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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                           NASA Science Activation
                             & Michigan Tech. U.

