Neutron stars are the angry ghost of giant stars: hot, rotating exotic cores thing left after supernovas. Like thermos full of hot noodle soup, eons need to be cooled. But now, researchers think they know how these stars do it: with a giant helping pasta.
No, these ultradense stellar corpses are not filled with spaghetti. Instead, neutron stars cool down by releasing ethereal particles known as neutrinos. And the new study shows that they did that work thanks to an intervening object known as nuclear pasta, a vibrant, coiled material in which almost all atoms, but not all together. This nuclear filling structure creates low-density regions within the stars, allowing neutrinos, and heat, to escape.
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A teaspoon of matter scraped from the surface of a neutron star will weigh billions of tons, more than every person on Earth combined. That density helps them catch the heat completely. And while our sun, considered a yellow dwarf star, emits most of its heat in the form of light, light particles produced within a neutron star rarely reach the surface to escape. However, these frantic undead stars – each the size of an American city – eventually calmed down, mostly through the release of neutrinos.
To understand how they cool down, the researchers of a new study, published October 6 in the journal Physical Analysis C, looked closely at the object inside the neutron stars.
Ordinary stars are made up of conventional objects, or atomo: tiny balls of protons and neutrons surrounded by relatively enormous clouds of electrons. In the meantime, the interior of neutron stars is so thick that the atomic structure breaks down, creating a vast ocean of so-called nuclear matter. Outside neutron stars, nuclear matter refers to matter inside atomic nuclei, dense balls of protons and neutrons. And it is governed by complex rules that scientists still do not understand
Pasta is what is between conventional matter and nuclear matter.
“Pasta is something that mediates between nuclear matter and conventional matter,” said co-author Charles Horowitz, a physicist at Illinois State University who eventually began to handle it, “Horowitz said. in Live Science. “And when they start touching, strange things happen.”
At some point, the pressures rise high enough that the structure of the conventional object completely collapses into the indistinguishable nuclear broth. But before that happens, there is a region of pasta.
In the pasta zone, the Coulomb repellent (the force that drives the particle charges) and the nuclear magnet (the force that binds protons and neutrons very little) begin to act against each other. In regions where the nucleus touches but the atomic structure has not yet been completely destroyed, objects are placed in complex shapes, called “pasta.” Scientists have words for different variations of these things: gnocchi, waffle, lasagna and anti-spaghetti.
“The shapes really look like pasta shapes,” Horowitz said.
Scientists have known for most of the last decade that this pasta is inside the neutron stars, just below their crusts in the region where conventional objects move to strange, less intuitive objects in nuclear. And they also know that neutrino emissions help cool neutron stars. A new study shows how pasta helps free neutrinos.
Top study author Zidu Lin, a postdoctoral researcher at the University of Arizona, designed a series of extensive computer simulations showing how neutrinos may appear in this unknown environment , Horowitz said.
The basic formula for making a neutrino into a neutron star is straightforward: A neutron that decomposes, transforms into a slightly lighter, low-energy proton and an ultralight neutrino. It is a simple process known to take place elsewhere in the galaxy, including our day. (Right in this second, a vast stream of solar neutrinos flows through your body.)
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But the conditions must be right for this recipe to work. And in a neutron star, conditions look wrong.
Neutron stars, as the name implies, have many neutrons, all zipping around high energy with a lot of momentum. But the neutrino recipe requires the production of a low-energy proton with almost no momentum. Momentum can not just be lost. It always saves. That’s it The New Law of Isaac Newton’s Motion. (This is also why if your car suddenly stops and you are not wearing a seatbelt you are flying out the window.)
Featherweight neutrinos cannot withstand all the momentum of relatively large and decaying neutrons. So the only place for momentum to go is to get out into the surrounding environment.
The dense, durable nuclear object is a terrible place for disposing of momentum. It’s like driving a sports car at high speed on a thick granite slab; the rock is barely moving and the car is pancakes because that momentum is nowhere to be found. Simple models of neutron star emissions struggle to explain how nuclear matter can capture enough momentum to escape neutrinos.
Lin’s model shows that nuclear pasta can solve most of this problem. Coiled, layered shapes have low density regions. And the pasta can be compressed, absorbing momentum in a rippling motion. It is as if that granite wall was mounted on a spring compressed to the impact of the car.
Researchers have shown that neutrino emissions from nuclear pasta are probably better than neutrino emissions in a neutron star core. That means pasta is probably responsible for most of the cooling.
This research, Horowitz said, suggests that neutron stars cool cooler than expected. That means they live longer. Histories of space-time should be tweaked, he said, to conceive their instability with extreme heat throughout the eons.
Originally published in Live Science.