The Southern Ring Nebula was formed by a pentagram

Thanks to the first data from the space telescope James Webbevidence was obtained that the complex conformation of Southern Ring Nebula It was caused by the death of a star that was part of a pentagram system.

Planetary nebulae

Despite their name, planetary nebulae have nothing to do with planets, they are large clouds of gas and dust that glow when illuminated by a very hot central star. Occur when stars like our Sun are in the final stages of their lives. They throw out so much material into outer space that they end up forming that cloud of gas and dust around them It expands as you get farther from the star. It is precisely because of this loss of material that the star goes from being gigantic and cold to being very hot and much smaller. The intense radiation from this stellar debris (the so-called white dwarf star) ionizes the surrounding material, causing it to shine brightly.

The Southern Ring (known as NGC3132 in astronomers’ parlance lies 2,000 light-years away in the constellation of the Shell), and is one of the planetary nebulae with the most fantastic morphology. Because of its multiple and complex symmetry. Not surprisingly, such a remarkable object was chosen by the James Webb Space Telescope for one of the first observations, published last July.

At first glance, one might guess that a planetary nebula is caused by the death of an individual star. But at least In the case of the southern ring, the situation turned out to be more complicated. In the images provided by the Webb telescope, the white dwarf star, which is primarily responsible for the nebula, is well visible in the central region. But, in addition, it is accompanied by a second, brighter star, which can interfere with the phenomenon of nebula gas ejection.

Exit of gases and dust

In order to determine the properties of the stars responsible for the formation of such a stunning nebula, an international team of astronomers coordinated Ursula DiMarco (Sydney Macquarie University) Combined Webb data with previous observations By telescope, as well as space, Gaia.

Analysis of this complete dataset showed that the central star (now a white dwarf) was less than three times the mass of the Sun before it ejected much of its matter and entered the final stage of its life. After multiple explosions, today the dying star It retained only 25% of its initial massThat’s only about two-thirds of the sun’s mass. Determining the star’s initial mass is essential to be able to reconstruct the sequence of events that caused the ejection of the gas and dust clouds that now make up the planetary nebula.

The data analysis was completed with some numerical simulations to try to explain the complex morphology observed. The two pictures at the top of this article Combined near and medium infrared data To isolate different components of the nebula. The image on the left highlights the superheated gas surrounding the central stars, while the image on the right is dominated by jets of molecular gas that propagate from the central region to great distances in space.

pentagram

DiMarco and his collaborators soon concluded that the dying star needed contributions from A small group of stars To be able to form all the very complex structures that can be seen today in the nebula.

For example, the arcs observed in the outer regions must have been created by an early companion star, while the brighter structures, which form an overlay of ovules, can only be explained by Two additional companions interact that they channeled mass loss from the dying star to create such eccentric shapes.

It’s true that Webb only notices a companion star next to the white dwarf, but other members of the star cluster can be much fainter and more Camouflaged by the brightness of two of the brighter. It cannot be ruled out that during the interaction of phenomena between them they may merge with the dying star.

The attached images show that up to 5 stars are needed to create all of the morphological complexity observed in the southern ring. The first frame (upper left) shows a broad field of Stars 1 and 2: the white dwarf and its much brighter companion, Webb noted. But, in addition, it shows the location of the star called “5”, which orbits near the white dwarf. In the second and third frames we approach the white dwarf (“1”) to discern the positions of stars 3 and 4, which They have to eject very narrow jets of matter responsible for certain shapes in the nebula.

In the next few frames (lower panels of the diagram) we zoom out to see how the stellar winds, along with the ultraviolet radiation, They carve out a series of recesses, more or less concentric. Star 1 is supposed to be surrounded by a dusty disk, and star 5’s interaction with this disk creates a system of large rings. The last panel (lower right) gives us a bird’s-eye view, on a grand scale, as the white dwarf (star 1) and its brighter companion (star 2) can be seen in the center of the ring, as it is revealed. by Webb telescope.

The result of this work, which requires 5-star collaboration, may seem surprising, but the fact is that the vast majority of stars form in binary and multiple systems or even in large swarms or clusters. On the other hand, there are many planetary nebulae that are not spherical, but rather flat The bipolar or multipolar forms appear, with multiple projectile marks in different directions. So it is reasonable to think that such shapes are due, in large part, to the presence of multiple stars in the central regions of the nebulae.

article Marco Ursula And his team, which includes several researchers from Spanish institutions, entitled The chaotic death of a multiple star system and the resulting planetary nebula as observed by JWST It was published in a recent issue of the prestigious magazine natural astronomy.

Raphael BSc He is the director of the National Astronomical Observatory (National Geographic Institute) and an academic at the National Geographic Institute Royal Academy of Physicians of Spain.