                        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 September 23
   Stars dot the frame that has a blue background. Covering the lower part
   of the image, and the far right, are brown and tan nebular structures.
          Please see the explanation for more detailed information.

                    NGC 6357: Cathedral to Massive Stars
     Image Credit: NASA, ESA, CSA, STScI, JWST; Processing: Alyssa Pagan
                                  (STScI);
          Rollover: NASA, ESA, HST, & J. M. Apellániz (IAA, Spain);
                 Acknowledgement: D. De Martin (ESA/Hubble)

   Explanation: How massive can a normal star be? Estimates made from
   distance, brightness and standard solar models had given one star in
   the open cluster Pismis 24 over 200 times the mass of our Sun, making
   it one of the most massive stars known. This star is the brightest
   object located in the central cavity near the bottom center of the
   featured image taken with the Webb Space Telescope in infrared light.
   For comparison, a rollover image from the Hubble Space Telescope is
   also featured in visible light. Close inspection of the images,
   however, has shown that Pismis 24-1 derives its brilliant luminosity
   not from a single star but from three at least. Component stars would
   still remain near 100 solar masses, making them among the more massive
   stars currently on record. Toward the bottom of the image, stars are
   still forming in the associated emission nebula NGC 6357. Appearing
   perhaps like a Gothic cathedral, energetic stars near the center appear
   to be breaking out and illuminating a spectacular cocoon.

       Teachers & Students: Ideas for Utilizing APOD in the Classroom
                     Tomorrow's picture: black hole bang
     __________________________________________________________________

       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.

