Just a couple of weeks after the publication of an image of the Ring Nebula, one of the most iconic planetary nebulae, captured by the James Webb Space Telescope’s NIRCam instrument, another image arrived, this time, captured by the MIRI instrument. Several filters were used to capture the emissions at various wavelengths in the mid-infrared to offer details that complement those offered by the NIRCam. The new details also indicate the presence of various compounds and about ten concentric arcs just beyond the outer edge of the main ring. These new results offer new insights into the processes taking place in the last stages of a star’s life and, in this case, the interaction with a possible companion.
Yet another study conducted on the Ring Nebula is once again showing the extraordinary potential of the James Webb Space Telescope. The near-infrared image captured by the NIRCam (Near Infrared Camera) instrument and published a couple of weeks ago had already shown that it can offer more detail than the Hubble Space Telescope. Now the MIRI (Mid-InfraRed Instrument) confirmed to have unprecedented spatial resolution and spectral sensitivity while also delivering mid-infrared detail.
This new image reveals in particular details about the concentric formations in the ring’s outer regions of the Ring Nebula. The position and relative proximity of a medium-small star in the last stages of its life make this object perfect for astronomical studies.
The over 20,000 clumps of molecular hydrogen cooler and denser than the rest of the nebula present in the ring were already clearly visible in the image captured by the NIRCam instrument. A surprise came when the MIRI instrument captured emissions from within the ring showing the chemical signature of polycyclic aromatic hydrocarbons (PAHs). These are hydrocarbons that are typically found in interstellar space and in clouds of cold molecular gas, where there’s star formation, not where a star is dying.
Another discovery made with the MIRI instrument was the ten concentric arcs just beyond the outer edge of the main ring. The reconstructions of their history indicate that these arcs formed about every 280 years as the star was ejecting its outer layers. The periodicity doesn’t match any known processes, and astronomers suspect that there’s a low-mass companion at a distance similar to Pluto’s from the Sun that interacts with the outflow of materials. It took the James Webb Space Telescope to offer enough detail to suggest the possibility of another star hidden by all the material ejected from its dying companion.
The ESSENcE (Evolved StarS and their Nebulae in the JWST Era) team is made up of planetary nebulae experts and participates in these new studies of the Ring Nebula. The results will be very interesting for all the astronomers who deal with these objects and are trying to reconstruct the last stages of life of a medium-small star.
