                        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 April 30
     A faint nebula runs vertically in the image. In the center is a red
    envelope surrounding diffuse blue emission. In the center is a bright
   multicolored nebula that is nearly circular. Please see the explanation
                       for more detailed information.

                      GK Per: Nova and Planetary Nebula
                Image Credit & Copyright: Deep Sky Collective

   Explanation: The star system GK Per is known to be associated with only
   two of the three nebulas pictured. At 1500 light years distant, Nova
   Persei 1901 (GK Persei) was the second closest nova yet recorded. At
   the very center is a white dwarf star, the surviving core of a former
   Sun-like star. It is surrounded by the circular Firework nebula, gas
   that was ejected by a thermonuclear explosion on the white dwarf's
   surface -- a nova -- as recorded in 1901. The red glowing gas
   surrounding the Firework nebula is the atmosphere that used to surround
   the central star. This gas was expelled before the nova and appears as
   a diffuse planetary nebula. The faint gray gas running across is
   interstellar cirrus that seems to be just passing through coincidently.
   In 1901, GK Per's nova became brighter than Betelgeuse. Similarly, star
   system T CrB is expected to erupt in a nova later this year, but we
   don't know exactly when nor how bright it will become.

                        Tomorrow's picture: sky fish
     __________________________________________________________________

       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
                  NASA Web Privacy, Accessibility, Notices;
                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

