RIT Professor Unveils the Hidden Secrets of the Iconic Ring Nebula’s Structure

The Ring Nebula is arguably one of the most captured objects in the nocturnal sky, with its earliest photograph taken in 1886. Its inherent structure has been a topic of discussion since it was first observed.

Researchers have now achieved the most distinct three-dimensional perspective of the nebula, all thanks to a research group led by Joel Kastner, a professor at Rochester Institute of Technology’s Chester F. Carlson Center for Imaging Science and School of Physics and Astronomy.

The group concluded that the nebula has an ellipsoidal form utilizing Submillimeter Array (SMA) radio-wavelength mapping of the emissions from carbon monoxide (CO) gas. The CO emissions expose cold, molecular gas that encases the hotter gas and dust evident in images of the nebula captured by the Hubble Space Telescope (HST) and, more recently, the James Webb Space Telescope (JWST).

“Upon analyzing the data, the ellipsoidal morphology was clear, enabling us to construct a straightforward geometrical model. Now, we grasp the form of this nebula,” stated Kastner. “The James Webb Space Telescope provides us with a flattened image of how the object appears in the sky. The SMA permits us to accurately gauge the velocities of the molecular gas within the nebula, allowing us to observe what is moving towards or away from us.”

Astronomers have speculated that the nebula is either ring-shaped or possesses a soap bubble configuration, yet the model derived from the SMA data indicated that it is an ellipsoid. The SMA findings elucidate the speeds and placements of the carbon dioxide molecules expelled by the dying star that formed the Ring Nebula, revealing its 3D structure, which cannot be deduced from telescopic images, even with powerful NASA space observatories like HST and JWST.

This modeling enabled astronomers to approximate that approximately 6,000 years have elapsed since the dying star, which was previously a red giant, expelled the molecular gas encasing the nebula. The SMA data also highlight distinct signatures of the impact of a companion star to the erstwhile red giant situated at the core of the nebula, manifesting as high-velocity blobs of gas that seem to have burst out from either end of the ellipsoidal shell.

These revelations follow comparable investigations conducted on the Southern Ring Nebula, one of the initial objects examined by the JWST. Kastner and his team authored a paper detailing a more profound comprehension of the Southern Ring’s structure in the spring of 2024. This novel technique of employing the combination of SMA mapping and JWST imaging to extract the 3D formations of these entities offers scientists a new approach to understanding the concluding, dying phases of sun-like stars.

“The stars that give rise to planetary nebulae like the Ring and Southern Ring might have generated a significant portion of the carbon in the universe,” remarked Kastner. “By monitoring that carbon as it moves toward being recirculated into the forthcoming generation of stars and planets, we gain insights when we observe these remarkable entities.”

Kastner is the principal author of a forthcoming paper regarding this new 3D perspective of the Ring Nebula, set to be submitted to The Astrophysical Journal. The research team included RIT astrophysical sciences and technology graduate students Diana Ryder and Paula Moraga Baez, who just attained her Ph.D. in the fall of 2024. Additional co-authors include David Wilner (Center for Astrophysics, Harvard & Smithsonian); Orsola De Marco (Macquarie University, Australia); Raghvendra Sahai (Jet Propulsion Laboratory); Al Wootten (National Radio Astronomy Observatory); and Albert Zijlstra (University of Manchester, UK). Kastner’s inquiry into molecular gas within planetary nebulae is supported by a grant from the National Science Foundation.