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For the first time, astronomers were able to follow with a wealth of detail and unparalleled proximity the “spaghettification” d’une étoile, partly devoured by a black hole, according to a study published on Monday.
The star, of a mass equivalent to that of our Sun, ventured too close to a supermassive ogre, with a mass a million times greater than him.
La plupart s’y perdent corps et bien, literally swallowed up by the phenomenal force of attraction of the black hole, that even prevents light from escaping.
But some experience progressive dislocation, dans ce que les astronomes appellent un effet de nouilles ou spaghettification. In the observed case, the star lost about half of its mass in the space of six months.
“This is exactly what happens in a tidal rupture event”, ou TDE, a dit l’astronome britannique Matt Nicholl, from the University of Birmingham, main author of the study.
Approaching, the star first flattens and then stretches under the effect of tidal forces from the black hole, taking the shape of a cigar, a expliqué à l’AFP Stéphane Basa, research director at the Marseille astrophysics laboratory: “When these forces exceed the cohesive force of the star, this one loses pieces that are engulfed in the black hole”.
One of the main contributions of the study, published in the Monthly Notices of the Royal Astronomy Society, is to better understand how matter is absorbed, in this case in the form of fine filaments.
The ingestion of these cosmic noodles is accompanied by powerful electromagnetic radiation, a light signal that signs the space glutton's package.
They enabled its automatic detection in September 2019, by a host of instruments detecting sudden changes in the luminosity of celestial objects, at about 215 million light years, in the Eridan galaxy.
“We immediately pointed a series of terrestrial and space telescopes in that direction to analyze the light source.”, a this Thomas Wever, co-author of the study, in a press release from the European Southern Observatory (THAT).
This glow is usually obscured by the curtain of matter, which makes it difficult to observe the phenomenon, according to scientists.
This time, the speed of the reaction and the relative proximity of the event helped lift part of the veil. “Nous avons pu observer un rideau de poussière et de débris s’élever quand le trou noir a projeté un jet puissant de matière à des vitesses allant jusqu’à 10.000 km per second”, said astronomer Kate Alexander, from Northwestern University, cited by ESO.
Another unpublished observation, selon Mr. Basa, some of the star's material is ejected from the other side of the black hole.
The astronomer validates the analogy of “Rosetta stone”, which made it possible to decipher the Egyptian hieroglyphics, utilisée par l’équipe du Pr. Nicholl, to qualify his discovery: “This is a textbook case for future observations”.
D’autant plus que les TED ne sont pas un phénomène courant. On estime qu’ils ne surviennent qu’une fois tous les dix mille ans dans une même galaxie.
Black hole, Spaghettification, Star, Astronomy, Observation, Supermassive black hole
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