Astronomers simulate the Cat’s Eye Nebula in 3D

In a recent study published in Royal Astronomical Society Monthly Notices, an international team of researchers led by Stanford University produced the first computer-generated 3D model of the Cat’s Eye Nebula, which unveiled a symmetrical pair of rings that surround the nebula’s outer shell. This study has the potential to help us better understand the composition of the nebula and how it formed, as the symmetrical rings provide clues that they were formed from a precessional jet, which produces a strong confirmation that a binary star exists at the center of the nebula.

The Cat’s Eye Nebula, also known as NGC 6543, is located approximately 3,000 light-years from Earth and is one of the most breathtaking images in the night sky. Like most planetary nebulae, it formed when the outer layer of gas was ejected by a dying solar-mass star. Images from the Hubble Space Telescope (HST) reveal an intricate composition of arc-shaped filaments, knots and spherical shells, which only adds to its beauty.

Cat’s Eye’s mysterious structure has stunned scientists for years, as they couldn’t figure out how traditional theories of planetary nebula formation could explain its complex shape. Research in recent years has demonstrated that precessional jets may act as shaping mechanisms in nebulae such as NGC 6543, but at the same time, a detailed model to support these claims has been lacking.

That was until Ryan Clairmont, a future Stanford University undergraduate, astronomy enthusiast and lead author of the study, took it upon himself to create a 3D structure of Cat’s Eye in the hope to explain its unique shape that traditional astrophysics struggled to explain. He enlisted the help of Dr. Nico Koning of the University of Calgary, who developed SHAPE, a 3D astrophysical modeling software suitable for modeling planetary nebulae, and Dr. Wolfgang Steffen of the National Autonomous University of Mexico.

For the study, the researchers used spectral data from the San Pedro Martir National Observatory in Mexico to reassemble the nebula’s 3D structure. By combining this data with images from HST, Clairmont was able to construct a new 3D model of Cat’s Eye, demonstrating that rings of high-density gas shrouded the nebula’s outer shell. The fact that the rings were almost perfectly symmetrical suggests that they were formed by a jet, which is a stream of high-density gas that is ejected from the nebula in opposite directions.

The jets themselves exhibited what is called precession, much like the oscillating motion of a spinning top. As the jet preceded over time, a circle formed that eventually created the rings we now observe around Cat’s Eye. However, the data shows that the rings were short-lived, meaning the precession jet never completed a full 360 degree circle. Since the time scale of the jet outbursts demonstrates important information regarding the global theory of planetary nebulae, the results indicate strong evidence that a binary star exists at the center of Cat’s Eye, since only binary stars are responsible for a planetary nebula. pretreatment jet.

As the direction and angle of the jet have changed over time, they are likely responsible for the current features we see in Cat’s Eye, including knots and jets. Armed with their new 3D model, the research team was able to calculate both the opening angle and the tilt of the precession jet depending on the orientation of the rings.

“When I first saw the Cat’s Eye Nebula, I was amazed by its beautiful, perfectly symmetrical structure,” Clairmont said. “I was even more surprised that its 3D structure was not fully understood. It was very rewarding to be able to do astrophysical research myself that really impacts the field. Precession jets in planetary nebulae are relatively rare, so understanding how they contribute to the formation of more complex systems like Cat’s Eye is important. Ultimately, understanding how they form provides insight into the eventual fate of our Sun, which will become itself. -even one day a planetary nebula.

As always, keep doing science and keep looking up!

Featured image: Side-by-side contrast of the 3D model of the Cat’s Eye Nebula produced by Ryan Clairmont and his research team and the Cat’s Eye Nebula as imaged by Hubble. (Credit: Ryan Clairmont (left) and NASA/ESA/HEIC/Hubble Heritage Team (Space Telescope Science Institute/AURA) (right); License type: Attribution-NonCommercial-ShareAlike (CC BY-NC-SA 4.0)