Stars Twinkle Sound Study: Scientists Say This is How ‘Twinkling’ Should Sound Like

A team of researchers takes a deep dive into core convection and its impact on the twinkling of stars. Uncover the untold story of stars and their fascinating twinkling.

The Innate Twinkle of Stars: A trailblazing study determines the innate twinkling of stars for the first time.

For many, the concept of stars twinkling has always been linked to the atmospheric distortions caused by the Earth’s atmosphere as the starlight travels through it. However, there’s another dimension to a star’s “twinkle” — the subtle stir of gas waves on the stellar surfaces — which has been nearly impossible to perceive with our existing terrestrial telescopes.

Now, an innovative study led by a team from Northwestern University has successfully created the first-ever 3D simulations of energy waves moving from a massive star’s core to its exterior surface. These newly developed models enabled the researchers to assess, for the very first time, the extent of a star’s inherent twinkle.

Taking another unprecedented step, the researchers transformed these undulating waves of gas into sound waves. This allowed for an auditory experience of the intrinsic sounds of stars and their mesmerizing “twinkle”.

The result is an eerily fascinating auditory journey.

The study was published today in the esteemed journal Nature Astronomy.

“Motions in the cores of stars launch waves like those on the ocean,” explained Evan Anders from Northwestern University, the lead author of the study. “When the waves arrive at the star’s surface, they make it twinkle in a way that astronomers may be able to observe. For the first time, we have developed computer models which allow us to determine how much a star should twinkle as a result of these waves. This work allows future space telescopes to probe the central regions where stars forge the elements we depend upon to live and breathe.”

Anders, a postdoctoral fellow at Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), is guided by study co-author Daniel Lecoanet, an assistant professor of engineering sciences and applied mathematics in Northwestern’s McCormick School of Engineering and a member of CIERA.

How does convection affect star twinkling?

The Turbulent Core Convection

Every star possesses a convection zone, a chaotic region where gases are continuously churning to propel heat outwards. For massive stars (those that have at least about 1.2 times the mass of our sun), this convection zone is situated in their cores.

“Convection within stars is similar to the process that fuels thunderstormsrms,” Anders explained. “Cooled air drops, warms and rises again. It’s a turbulent process that transports heat.”

This turbulent process generates waves — small ripples that cause the starlight to dim and brighten, inducing a subtle twinkle. Anders and his team, with the objective of modeling the hidden convection of the cores of massive stars, have built upon previous studies that examined properties of turbulent core convection, characteristics of waves, and potential observational features of these waves. Their novel simulations incorporate all relevant physics to precisely predict how a star’s brightness changes depending on the waves generated by core convection.

How can we hear a star twinkle?

A Symphony in Stars

In an approach similar to sound engineering in a music studio, the team managed to transform the waves from their simulations into sound. Given that these waves are beyond the range of human hearing, they increased the frequencies of the waves to make them audible.

Depending on the size or luminosity of a massive star, the convection creates waves corresponding to different sounds. For instance, waves emerging from the core of a large star create sounds reminiscent of a distorted ray gun, resonating through an alien landscape. However, as these waves reach the star’s surface, the pulses transition into a low echo reverberating through an empty room.

Looking forward, Anders and his team plan to utilize different-sized stars to observe how they transform songs. By passing a short audio clip from “Jupiter” (a movement from “The Planets” orchestral suite by composer Gustav Holst) and from “Twinkle, Twinkle, Little Star” through various massive stars, they aim to explore the resulting distant and haunting sounds — as if drawn from “Alice in Wonderland.”

Anders concluded, “We were curious how a song would sound if heard as propagated through a star. The stars change the music and, correspondingly, change how the waves would look if we saw them as twinkling on the star’s surface.”

The study was backed by CIERA, NASA, and the National Science Foundation.

What Does a Star’s Twinkle Sound Like?

Source: 10.1038/s41550-023-02040-7

Image Credit: Stil from the video