(ORDO NEWS) — The sinuous eruption of a dying star is finally revealed in all its three-dimensional splendor.
A team of scientists led by a high school graduate has reconstructed the complex and mysterious nebulae that make up one of the most famous stellar ghosts in the sky, the Cat’s Eye Nebula.
Their model revealed the mechanisms that shaped some of the previously unexplained aspects of the nebula’s structure.
The results may help us understand other nebulae of this kind, and it gives us some idea of what might happen to our own Sun.
The Cat’s Eye Nebula, also known as NGC 6543, is known as a planetary nebula. However, they are not related to the planets at all; the term arose because their round shape resembles planets.
Such nebulae are what remains after a star like the Sun runs out of fuel to burn and reaches the end of its life.
Although planetary nebulae share common characteristics, the Cat’s Eye Nebula is one of the more complex examples discovered to date.
Although generally round in shape, the inside is dominated by a rhomboid shape, similar to the pupil of a cat’s eye, filled with knots, shells, and filaments.
It is one of the most studied nebulae in the world. the sky too, but some aspects of its structure are still a bit puzzling.
They cannot be easily explained within the framework of the modern model of the formation of planetary nebulae, called the model of interacting stellar winds.
According to this model, the star expands into a red giant (like Betelgeuse) and generates a slow stellar wind that pushes stellar material into space.
Then, at the end of this life stage, the star ejects its outer material into space, and the core, no longer supported by the external pressure of nuclear fusion, collapses under gravity to form a white dwarf.
A very hot white dwarf creates a fast stellar body. wind that cuts into material in slower winds, shaking the gas and creating shells.
The point-symmetric bipolar shape of the Cat’s Eye Nebula a does not fit into this model.
“When I first saw the Cat’s Eye Nebula, I was struck by its beautiful, perfectly symmetrical structure,” explains Ryan Claremont, who plans to attend Stanford University. “I was even more surprised that its three-dimensional structure was not fully understood.”
So he did something about it. He enlisted the help of astronomers Wolfgang Steffen of the National Autonomous University of Mexico and Niko Koning of the University of Calgary in Canada, and used the SHAPE astrophysical modeling software to deconstruct what is happening inside the central region of the Cat’s Eye Nebula.
The Hubble Space Telescope, which made incredibly detailed observations of the nebula in 2008, provided some of the data used.
They also used spectral data from the San Pedro Martir National Observatory in Mexico, which show the movement of gas within the nebula.
The 3D model they built revealed something interesting: spiraling rings of high-dense gas partially wrapped around the nebula’s outer shell, symmetrically arranged around its two lobes.
This symmetry suggests that the rings are the result of high-velocity jets ejected from the star’s poles at the center of the cat’s eye.
As the star that gave birth to them wobbled like a top – a motion called rotational precession – this caused the jets to emerge in a spiral shape.
Their incompleteness means that the jets erupted only for a short time. before being interrupted.
The only phenomenon known to us capable of producing a precessing jet in a planetary nebula is a binary star.
The star at the center of the Cat’s Eye is thought to be a Wolf-Rayet type star, not quite a white dwarf yet, but just around the corner, still losing mass as the last of its fuel is burned. These stars combined with another star can create some truly impressive nebulae.
Previous research has suggested that a double companion may be lurking at the center of the Cat’s Eye Nebula. This new discovery supports this interpretation.
Future observations and analysis will be able to take this model into account to better interpret the strange dynamics of this fascinating nebula.
“It was a great pleasure for me to do my own astrophysical research, which really makes a difference in this area,” Claremont says.
“Precessing jets in planetary nebulae are relatively rare, so it is important to understand how they influence the formation of more complex systems such as the Cat’s Eye.
Ultimately, understanding how they form provides insight into the possible fate of our Sun, which will one day become a planetary nebula itself.”
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