Subj : Daily APOD Report To : All From : Alan Ianson Date : Tue Sep 23 2025 00:10:26 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. Apell+íniz (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. --- BBBS/Li6 v4.10 Toy-7 * Origin: The Rusty MailBox - Penticton, BC Canada (1:153/757) .