Our sun may not be quite as big as we thought: science alert

The star at the center of our solar system – the Sun – may be infinitely smaller than scientists think.

A team of two astronomers has now found evidence that the radius of our Sun is a few hundredths smaller than previous analyses.

That may not seem like a lot, but it could make a big difference in how scientists understand the glowing ball of light that keeps our planet alive.

The new findings, which are currently undergoing peer review, are based on sound waves generated and trapped within the hot plasma in the Sun’s interior, called “pressure” or p-modes. Like a rumbling belly, these ringing sounds can do just that Indication of pressure changes It occurs within the solar alimentary canal.

According to astrophysicists Masao Takata of the University of Tokyo and Douglas Goff of the University of Cambridge, p-mode oscillations allow a “more dynamically robust” view of the Sun’s interior than other oscillating sound waves.

To understand what this means, it’s easier to imagine the Sun as a ringing bell, although it’s not a bell that’s struck once — which is the bell discovered by scientists at Stanford University. Describe It is constantly hit “by many small grains of sand.”

All that seismic noise Produces Millions of sound waves or oscillating “patterns,” which scientists can measure remotely.

In addition to the push and pull of p waves, there are ripples that sway up and down under the influence of gravitational force, called g modes, which are referred to as f modes when they occur near the surface of the star.

As stars become denser, other modes can arise that can be used to describe the properties of the object.

F modes are particularly useful for studying the hot, swirling plasma in the Sun’s interior, while p modes are extremely useful for capturing the Sun’s “spherical harmonics.”

This is because p-modes exist They are produced by pressure fluctuations In the interior of the sun. When these waves move outward, they strike the Sun’s surface (its photosphere) and are reflected back inward, bending as they travel through the turbulent plasma to bounce off another part of the Sun’s surface.

Combining a huge number of these modes can build a picture of the Sun’s structure and behavior.

But which one do you choose?

The traditional reference model for the Sun’s seismic radius is based on the modes f, where they are measured first.

But F modes, some astronomers say, are not completely reliable, because they do not extend directly to the edge of the Sun’s photosphere. Instead, they seem to “knock” on what Takata and Goff call the “imaginary surface.”

P modes, According to some previous researchThey reach further, because they are less susceptible to magnetic fields and disturbances in the upper boundary layer of the Sun’s convection zone.

When determining the Sun’s radius based on seismic measurements (rather than on visible light or thermal calculations), Takata and Goff argue that p-modes are the optimal solution.

Their calculations using only p-mode frequencies indicate that the radius of the solar photosphere is very slightly smaller than the standard solar model.

It doesn’t matter how small the error is, astrophysicist Emily Brunsden says Tell Alex Wilkins in New World RChanging the more traditional model to accommodate such results will not be easy.

“Understanding why they are different is difficult,” Brunsden He said“Because there are a lot of things going on.”

The pre-print paper was published on arXiv.