The most detailed 3D map of the interiors of the stars reveals their main secret

The stars are arranged quite simply. Gravity compresses the star, trying to destroy it, which causes the inner core to become extremely hot and dense. This triggers the process of nuclear fusion, and the heat and pressure from it repel gravity. These two forces balance each other while the star is in the main sequence state. But the details of how it works are extremely complicated.

3D simulation of convection inside a star

Accurate modeling of the internal structure of a star requires complex computer models, and even then, it can be difficult to match the model with what we see on the surface of the star. Now a new computer simulation is helping to change this situation.

Heat and energy output

Although the internal pressure and gravitational weight of a star are usually in equilibrium, the heat flow is not. All the heat and energy generated in the core of a star must eventually come out of it, and there are two main ways in which this happens.

The first is through radiation exchange. High-energy gamma rays are scattered on the nuclei in the core, gradually losing some of the energy as they migrate to the surface and come out. The cores of the star are so dense that it can take thousands of years.

The second method is through a convective flow. Hot matter near the center of the star is trying to expand, making its way to the surface. Meanwhile, the colder substance at the surface condenses and descends to the core.

Together, this creates a cyclic flow of matter that transfers thermal energy to the surface of the star. This convection is stirring the interior of the star, and due to factors such as viscosity and turbulent vortices, it is extremely difficult to model.

Usually stars have a radiative zone and a convective zone. The location and size of these zones depend on the mass of the star. Small stars are almost completely convective, whereas stars like the Sun have an internal radiation zone and an external convective zone.

For massive stars, everything is the opposite, with an internal convective zone and an external radiation zone. One of the things we know about convection is that it can cause the surface of a star to oscillate like a boiling pot of water. This, in turn, causes the overall brightness of the star to flicker slightly.

What affects the flicker?

In this new study, the team shows how convection regions in a star are related to how they flicker. Scientists have found that the sound waves that pass through the star are affected by convective flows, which, in turn, change the way the star flickers.

This means that, in principle, we can study the interior of a star by observing its flickering, which will allow astronomers to better understand them. Now the flickers are too small to be observed with modern telescopes. But with the help of larger and more sensitive telescopes, we will be able to study them.

We can already study the effect of sound waves on the Sun using the so-called helioseismology. In the coming decades, we will be able to do this with the nearest stars.

According to Sciencealert

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