An image captured by the James Webb Space Telescope shows the Ring Nebula, one of the most iconic planetary nebulae, in new details that reveal the complexity of the processes taking place during the last phase of the life of a small to medium star thanks to the NIRCam (Near Infrared Camera) instrument’s ability to detect infrareds. A team of researchers led by Mike Barlow of UCL (University College London) is studying the Ring Nebula as a target of the JWST Ring Nebula Project, of which Barlow is the lead scientist. The study is still ongoing, but Barlow stated that Webb’s high-resolution images not only show details of the expanding nebula’s shell but also reveal the inner region around the central white dwarf with exquisite clarity.
The name planetary nebula is due to a misinterpretation by astronomers who in past centuries used telescopes that today would be considered amateurish. For a long time, it’s been known that this type of nebula forms in the last stages of the life of a medium-small star, when the red giant phase ends and layers of gas are ejected into interstellar space. Those materials get ionized by the radiations coming from the dying star, determining their brightness with different colors for each chemical element.
About 2,600 light-years away from Earth, the Ring Nebula, also cataloged as Messier 57 or NGC 6720, has been known for over two centuries and was studied with increasingly powerful instruments. Astronomers have much better telescopes today than they did in the days when these objects were thought to have a planetary nature, but they are still trying to understand the details of the processes taking place. The James Webb Space Telescope is helping in this task.
The Hubble Space Telescope already showed a hitherto unknown complexity in planetary nebulae, including the Ring Nebula, with clumps of gas and filaments extending outward. All of these details were revealed to a new level of quantity and quality by the James Webb Space Telescope.
The star at the center of the Ring Nebula, which is becoming a white dwarf, was already known and around it, there’s a large amount of ionized gas ejected in the course of its agony. The ring that gives this nebula its name occupies the outermost part and the NIRCam instrument shows that it’s made up of over 20,000 clumps of molecular hydrogen that is colder and denser than the rest of the nebula.
Astronomers are interested in the processes taking place in planetary nebulae to better understand the last stages of life of medium-small stars. These phases don’t last long in astronomical terms, a few tens of thousands of years, and then disperse into interstellar space. Precisely this process represents another reason of interest for astronomers, as those elements can contribute to the formation of new stars and new planets. Upcoming images of the Ring Nebula, in this case, captured by the James Webb Space Telescope’s MIRI instrument, will offer further details.
