Une étoile peu massive en fin de vie éjecte ses couches externes tandis que son cœur se change en naine blanche. © Nasa, ESA

This 4-star system could trigger a rare supernova!

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[EN VIDÉO] Binary systems of stars and black holes
NASA-made assembly of 22 binary systems comprising a star and a stellar-mass black hole. Their dances are accelerated 22,000 times and shown as seen from Earth. The colors of stars and accretion disks surrounding black holes reflect their temperatures. ©NASA

In 2017, researchers at the University of Canterbury in New Zealand discovered a quadruple system ofStars, since called HD74438. More precisely, it is a binary star system binaries : a first with a orbit near and fast, and the other much more distant and slower. In a new magazine publication natural astronomyout of astrophysicist Study the possible evolutions of this system based on numerical modelling
Numerical modeling consists of building a set of functions…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/a/0/8/a0817e96b9_50037926_soleil-simulation-vibrations- sismology . jpg” data-url=”https://news.google.com/sciences/definitions/matiere-modelisation-11321/” data-more=”Read more”>Model the orbit of each star it contains.

The youngest quadruple system ever found

Located in the set of small satellites…” data-url=”https://news.google.com/sciences/definitions/universe-constellation-21/” data-more=”Read more”>constellation of Vela visible only in the southern hemisphere in geography
The Southern or Australian Hemisphere corresponds to the geographic area that extends between the poles…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/2/8/1/281a5ce994_50038918_southern -hemisphere -luis-miguel-bugallo-sanchez-wikimedia.jpg” data-url=”https://news.google.com/planet/definitions/geography-southern-hemisphere-12813/” data-more=”Read more” >southern hemisphereHD74438 was discovered by the during a monitoring campaign ESA satellite Gaiawhich has already identified more than 100,000 stars in ours galaxy. Then everything was done thanks spectrographs in the climax resolution based at the University of Canterbury in New Zealand and the Southern African Large Telescope in South Africa. They enable the characterization of light spectrum of the starthat is, to decompose the white light
The wavelengths of visible light range from about 380 nm (violet) to 780 nm (red). The visible spectrum is…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/b/6/9/b697a0c09f_85912_lumiere.jpg” data-url=”https:// news.google.com/science/definitions/physics-light-326/” data-more=”Read more”>bright it emits and analyze the intensity for each wavelength. Thanks to this method, they can deduce not only the temperature of the star, but also its composition the atmosphere.

That star system 43 million years old is still young, because if that seems long, we should remember that our sun is the closest star to Earth, from which it is about 150 million kilometers away. The Sun is 8.5 kParsecs from the center of the Milky Way. In the stellar classification, the Sun is a G2 type star.
The mass…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/1/d/9/1d9cd1d45f_50034577_eruption.jpg” data-url=”https://news. google.com/sciences/definitions/univers-soleil-3727/” data-more=”Read more”>Sun It is already 4.6 billion years old! This makes it the youngest quadruple system found to date. These four-star plants are rare, in the order of a few percent multiple systems which are already quite rare and have complex evolutions. In this particular case, the binary system Outer exerts a gravitational pull on the inner system and tends to warp the orbits of its two stars.

A future thermonuclear supernova?

To model the possible evolutions of HD74438, the team of scientists modeled the gravitational effects driving the quadruple system. They showed that theeccentricity of the internal system tended to increase. In practice, this means that the trajectory becomes less and less circular: a collision could be triggered after this deviation between a star of each system.

And the result of this collision would be… first of all, a white dwarf ! He is not here yet thermonuclear supernova long awaited. “ A star like our sun will end its life as a small, dense, dead star known as a white dwarf Dimensions White dwarfs cannot exceed the so-called Chandrasekhar limit (about 1.4 solar masses).”explains Professor Karen Pollard, first author of the study and astrophysicist at the University of Canterbury. “If so, either due to mass transfer events or the melting point of water, which is the temperature at which the ice…” data-image=”https ://cdn.futura-sciences.com/buildsv6 /images/midioriginal/7 /d/0/7d0df59f3c_82086_fusion.jpg” data-url=”https://news.google.com/sciences/definitions/physics-fusion-15305/” data-more=”Read more”>merger, it can collapse and create a thermonuclear supernova. » And that’s exactly what would happen with HD74438!

“The evolution of star quads like HD 744384 therefore represents a promising new way to detect thermonuclear supernova explosions in The history of the universe begins about 13.7 billion years ago in an extremely dense and hot soup. The laws of physics as we…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/1/5/5/1557798396_80921_universe.jpg” data-url=”https : //news.google.com/sciences/definitions/astronomy-universe-15239/” data-more=”Read more”>universe, closes them. fInterestingly, 70% to 85% of all excerpts from …” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/a/9/4/a940132305_50034136_supernova1987a.jpg” data- url =”https://news.google.com/sciences/definitions/universe-supernova-60/” data-more=”Read more”>supernova It is now believed that thermonuclear cells result from the explosion of sub-Chandrasekhar-mass white dwarfs. B. through mass transfers or mergers, these dwarf stars White can explode in a thermonuclear supernova. » What question do the current models of thermonuclear supernovae ask?

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