A screenshot of a simulation showing the pulsations of the star HD 31901
Chris Boshuizen / Simon Murphy / Tim Bedding
The stars speak! The understanding of stars, including our own sun, has mainly focused on examining them Outsides: the surfaces and the surrounding atmospheres that we can see. Although we cannot appearance In a star we can hear the rumble that it makes due to pulsations and vibrations inside. By studying the impulses, astronomers can see what is happening in the heart of a star.
For a certain class of stars known as Delta Scuti stars, it was difficult to determine the rhythm. Thanks to NASA’s latest space telescope for planet hunting, astronomers have now pulled the insanely hot curtain of this class of stars away to get a feel for what is happening inside.
A new study published in the journal Nature On Wednesday, the rhythm of dozens of Delta Scuti stars is described in detail, which are about twice as massive as our sun. Clear, obvious rhythms are determined. The discovery offers astronomers a new way to understand the unusual physics in the hearts of these stars, which are relatively common across the galaxy.
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To tune into the interior of the stars, astronomers at the University of Sydney applied Transiting Exoplanet Survey Satellite from NASAwho has performed one extensive overview of the cosmos since its launch in 2018. The satellite is said to chase planets around other stars by dividing the sky into sectors and taking snapshots of all the blazing ovens in its field of view. Every two minutes, TESS captures a quick picture of the sky and measures the brightness of thousands of stars to see how this changes over time. A drop in brightness could correspond to a planet passing in front of the star.
But the research team wasn’t looking for distant planets. Instead, the extremely precise changes in brightness recognized by TESS were used to observe the stars themselves. The incredibly small changes in brightness correspond to pulsations and vibrations in the heart of the star. Because TESS can exquisitely resolve the brightness of stars, a great set of data is created to try to hear a star’s heartbeat.
The team focused on a series of TESS data with a sample of 92,000 stars and was able to use clever coding to develop a tool with which the huge data set can be quickly searched. A random finding in the TESS data led to a list of around 1,000 stars with similar rhythms. Finally, the researchers managed to pin down the list to 57 Delta Scuti stars with recognizable rhythms.
The stars are all galactically relatively close to us and are between 60 and 1,400 light years away. As a reference, the Milky Way is over 100,000 light years wide.
Tim Bedding, an astronomer at the University of Sydney and lead author of the paper, said the new data allowed his team to “eliminate the noise”.
“We used to find too many jumbled notes to properly understand these pulsating stars,” he said in a press release. “It was a mess like listening to a cat walking on a piano.” It became much clearer with the TESS data. Bedding now says it’s more like “listening to beautiful chords”.
The rhythms of many other types of stars have been discovered in recent decades, including that of huge red giants like BetelgeuseThis has allowed astronomers to determine what is happening in the red-hot gas balls. Although Delta Scuti stars are widespread across the universe, previous research has failed to find a regular rhythm.
“We think that’s because they spin quickly, which makes the patterns less regular,” said Bedding.
With a pulse pattern now understood, future research will be able to more accurately determine the age of stars and help astronomers figure out how galaxies and star systems could develop.
“We are now able to examine these stars and use them as a benchmark to interpret the large number of other stars in the group that present more complex pulsation spectra,” said Bill Chaplin, astronomer at the University of Birmingham and co- Author of the study.
NASA’s TESS is still monitoring the sky, sending mountains of data back to Earth every month. Bedding says it is sometimes compared to “drinking from a fire hose” and there are many more sectors to look through. His team will now study other, more complex Delta Scuti stars to see if they can identify patterns.