by The Southern Ring Nebula is a cocoon of dying stars that is booming — and it has a secret. Scientists have discovered that this nebula exhibits a double ring structure which indicates that there is not one, but possibly three stars at its heart.
The Southern Ring Nebula, also named NGC 3132, is a planetary nebula located at about 2,000. light year away in the constellation Vela, the Willows. The name “planetary nebula“It’s a misnomer — those nebulae have nothing to do with it planets. Instead, they are the last exhalations of dying, Sun-good stars, transformed inside the nebulous chrysalis until finally blooming into a white dwarf. A nebula is formed from the outer envelope of a dying star, which is puffed into it space following the star red giant step.
The Southern Ring Nebula was imaged in December 2022 by the James Webb Space Telescope (JWST), which showed molecular hydrogen gas that forms the nebula on an “exoskeleton.” This refers to hot gas that radiates with a temperature equal to about 1,000 kelvin (1,340 degrees Fahrenheit, or 726 degrees Celsius) as it is illuminated and heated by ultraviolet light coming from the white ox own. That exoskeleton, however, represents only a small fraction of the molecular gas in the nebula.
Related: The Horsehead Nebula rears its head in stunning new James Webb Space Telescope images (video)
A team led by Joel Kastner of the Rochester Institute of Technology went in search of more of the nebula’s molecular gas, looking specifically for carbon monoxide gas using the Submillimeter Array (SMA), a group of eight radio telescopes on an inactive volcano that Mauna’s name. Kea in Hawaii. Carbon monoxide is mixed with hydrogen and other molecular gases inside the nebula, so looking at the carbon monoxide content is a proxy for looking at all those other less easily detectable molecules. Sure enough, the SMA was able to measure the distribution and velocity of the carbon monoxide molecules, showing which parts are moving towards us and which are moving away from us.
“JWST showed us the hydrogen molecules and how they pile up in the sky, and the Fomillimeter Array shows us the cooler carbon monoxide that you can’t see in the JWST image,” Kastner said in a. press release.
As the name Southern Ring suggests, it is primarily formed (from our point of view) as a ring. The SMA observations showed that this ring is expanding, which would be expected as the nebula slowly grows before finally dispersing. However, the data allowed Kastner’s team to create a three-dimensional map of the nebula’s molecular exoskeleton. This surprised people. Not only were the researchers able to show that what we see as a ring is just a lobe in a bipolar nebula seen at the end of the end, but they also found second ring perpendicular to the first.
“When we started turning the entire nebula around in 3D, we immediately saw that it was really a ring, and then we were surprised to see that there was another ring,” said Kastner.
The whole strange arrangement paints an interesting tail of not one, not even two, but possibly three stars at the center of the nebula. Only one of these stars, the largest star of the three, will have reached the end of its life – but the three stars, if there really are three, are likely to be too close to each other or too small to solve separately, even. at the JWST.
There is growing evidence that some planetary nebulae, at least those that sport complex structures, have formed from the intrusion of a companion star into the dying central star. Regarding the Southern Ring, Kastner’s team considers that a triple system is made of closure binary which is orbited by a third more distant star within a 60 radius orbit astronomical units of the binary (one astronomical unit, AU, the distance between World and the sun, and in our Solar system 60 AU would be out at the far edge of the Kuiper belt).
The two lobes of the Southern Ring have a narrow, or “pinched,” hourglass-like waistline, which is a common feature of planetary nebulae arising from a binary star system in which one of the stars is nearing the end of its life. The companion binary is able to corral the material lost by the dying star so that it escapes along a polar direction, rather than an equatorial direction, forming the two lobes. JWST’s mid-infrared observations support this hypothesis, having detected an excess of infrared light coming from the central star system, which is a classic signature of a dusty disk formed by interactions between the red giant and a close binary companion.
So that explains the first ring. The origin of the second ring, the team says, is less certain.
Although the Southern Ring appears to be bilobed, there must have been some ejected material as a rough spherical or ellipsoidal envelope of material thrown out by the red giant, a rapid mass ejection event that could possibly represent a final exhalation of matter to leave blank. an ox The binary star system produces a series of narrow fast jets, but if a third star is present, then the additional star gravity act on the inner binary, causing the direction of the jets to “wobble,” like a spinning top. The previous jets would have carved a circular hollow in the ellipsoidal component of the nebula, creating a second ring.
Kastner emphasizes that this explanation is still speculative, but there is evidence of such jets in their structure in the nebula’s central ionizing cavity.
Other ring-shaped planetary nebulae, such as the Helix Nebula (NGC 7293 in Aquarius), it has also been shown that there are bi-lobed structures through which we are looking “down” the end of one lobe. The discovery of a second ring in the Southern Ring Nebula — or should that be Southern Rings, plural? — encouraging astronomers to visit some of those other known ring astronomers to see if they’ve lost second rings in them as well.
Planetary nebulae are not just stellar deaths. They also have the promise of new life — literally, in a way.
“Where is the carbon and the oxygen and the nitrogen i the universe come from?” Wonder Kastner. “We are seeing it generated in the stars like a dying sun, like the star that just died and created the Southern Ring.”
Related Stories:
— The James Webb Space Telescope reveals a neutron star hidden in the wreckage of a supernova
—The James Webb telescope discovers the earliest thread in the ‘cosmic web’ ever seen
— James Webb Space Telescope view of Earendel, the most distant known star in the universe
As an expanding planetary nebula spreads inward interstellar spaceit spreads those molecules throughout the cosmos, where they end up in great molecular clouds that form the next generation of stars and planets.
“Much of that molecular gas would wind up in planetary atmospheres and the atmosphere can enable life,” says Kastner. In fact, all the elements on Earth heavier than hydrogen and helium originated inside stars and were then expelled into space when those stars died.
We are literally star material, as many experts like to say.
So, when we marvel at the beauty of the death of a star in a nebula like the Southern Ring, we can also imagine it as a starry phoenix that will one day rise from the ashes and begin the cycle of birth and death. horoscope again. To quote Battlestar Galactica, this has all happened before, and this will all happen again.
The results were published on 2 April i The Astrophysical Journal.
