Stephan’s Quintet is most famous for its appearance in It’s a Wonderful Life, and I really enjoy privately mulling over the absolutely astonishing improvements in imaging, physical understanding, and even humility that have occurred between the time when the image appeared in the film and the time when this JWST image was taken. However, I am not so foolish as to think that students yet enjoy that type of perspective. So, I share it with you but stick to the astronomy with my students!
Four of the large galaxies in this image are close together in space, but the leftmost one is in the foreground by about 250 million light years. The others are all about 290 million light years away. The interaction between the top three galaxies that are near to one another is extraordinary. Bright red star-forming regions really pop out in this image, as do the jets emitted from the AGN in the top galaxy. There’s a nice tidal tail to the left of that topmost galaxy, and the merging galaxies right below that topmost one really give a sense of motion and inspiral.
The background to the quintet is also interesting, with lots of galaxies of various colors, sizes and shapes.
Supporting material in the texts and online: This image provides a great opportunity to talk to students about “What an Astronomer Sees”--how astronomers draw meaning out of an image by closely examining shapes, colors and relationships. You might reference this image in the chapters on the Formation and Evolution of Structure, because it so clearly shows that galaxies merge and evolve. Other connected material appears in:
Exploration: Galaxy Classification, where this image could be substituted for the image shown. Students can zoom in and identify galaxies of each type on a printout or grid.
AstroTour: Active Galactic Nuclei, which relates to the AGN in the top galaxy.
Astronomy in Action Video: Size of Active Galactic Nuclei and Galaxy Shapes and Orientation.
Hubble Law, where the connection between redshift and distance (of galaxies in the background, for example) is made concrete.
The Learning Astronomy by Doing Astronomy Workbook, Activity 28: Light Travel Time and the Size of a Quasar can help students understand why they can’t actually SEE the AGN at the bottom of the jets in the topmost galaxy.