Researchers capture musical pulses coming from distant Delta Scuti stars and find some appear to HAR

[Judi Lynn]

Researchers capture musical pulses coming from distant Delta Scuti stars and find some appear to HARMONIZE with each other

By MICHAEL THOMSEN FOR DAILYMAIL.COM

PUBLISHED: 16:01 EDT, 14 May 2020 | UPDATED: 16:11 EDT, 14 May 2020

Star pulses are observed by measuring variances in the light waves emitted by a star, which can be disrupted by internal sound waves produced by burning hydrogen, or small waves produced as different bodies of gas in the star center pass through or near each other.

'Within stars these pulsations cause the brightness of the star to change periodically - it gets hotter and brighter, or it gets darker,' University of Birmingham's Bill Chaplin told Sky News.

'The pulsations for astronomy are quite a big deal, it gives us the only way of building up a detailed picture of what the inside of a star looks like.'

'If we measure the periods or frequencies of the harmonics of the star, they tell us about its internal structure.'

The readings were taken from data first collected by NASA's Transiting Exoplanet Survey Satellite, which launched in 2018 with the goal of identifying planets outside our solar system

The discovery could also be useful in helping researchers detect how old a star is, as newer stars tend to burn at a relatively consistent rate, while older stars develop more erratic pulses.

The harmonizations seen with the Delta Scuti stars are still a mystery, but one explanation could be that they all formed from the same larger gas cloud around the same time before dispersing through the universe.

More:
https://www.dailymail.co.uk/sciencetech/article-8320533/Researchers-capture-musical-pulses-coming-distant-Delta-Scuti-stars.html

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May 13, 2020
NASA’s TESS Enables Breakthrough Study of Perplexing Stellar Pulsations

Astronomers have detected elusive pulsation patterns in dozens of young, rapidly rotating stars thanks to data from NASA’s Transiting Exoplanet Survey Satellite (TESS). The discovery will revolutionize scientists’ ability to study details like the ages, sizes and compositions of these stars — all members of a class named for the prototype, the bright star Delta Scuti.

“Delta Scuti stars clearly pulsate in interesting ways, but the patterns of those pulsations have so far defied understanding,” said Tim Bedding, a professor of astronomy at the University of Sydney. “To use a musical analogy, many stars pulsate along simple chords, but Delta Scuti stars are complex, with notes that seem to be jumbled. TESS has shown us that’s not true for all of them.”

A paper describing the findings, led by Bedding, appears in the May 14 issue of the journal Nature and is now available online.



A looping GIF shows a bright star pulse once then reveals internal sound waves traveling between the star's center and surface.

Sound waves bouncing around inside a star cause it to expand and contract, which results in detectable brightness changes. This animation depicts one type of Delta Scuti pulsation — called a radial mode — that is driven by waves (blue arrows) traveling between the star’s core and surface. In reality, a star may pulsate in many different modes, creating complicated patterns that enable scientists to learn about its interior.
Credits: NASA's Goddard Space Flight Center

Hear the rapid beat of HD 31901, a Delta Scuti star in the southern constellation Lepus. The sound is the result of 55 pulsation patterns TESS observed over 27 days sped up by 54,000 times. Delta Scuti stars have long been known for their apparently random pulsations, but TESS data show that some, like HD 31901, have more orderly patterns.
Credits: NASA's Goddard Space Flight Center and Simon Murphy, University of Sydney

. . .

"Delta Scuti stars have been frustrating targets because of their complicated oscillations, so this is a very exciting discovery," said Sarbani Basu, a professor of astronomy at Yale University in New Haven, Connecticut, who studies asteroseismology but was not involved in the study. "Being able to find simple patterns and identify the modes of oscillation is game changing. Since this subset of stars allows normal seismic analyses, we will finally be able to characterize them properly."

The team thinks their set of 60 stars has clear patterns because they’re younger than other Delta Scuti stars, having only recently settled into producing all of their energy through nuclear fusion in their cores. The pulsations occur more rapidly in the fledgling stars. As the stars age, the frequency of the pulsations slows, and they become jumbled with other signals.

More:
https://www.nasa.gov/feature/goddard/2020/nasa-s-tess-enables-breakthrough-study-of-perplexing-stellar-pulsations

[tblue37]

1. The music of the spheres. nt

[abqtommy]

2. Exactly!

[Judi Lynn]

3. "The Planets"