The 'beating hearts' of these pulsating stars create music to astronomers' ears

Previously undetectable, a group of international astronomers utilizing data from NASA's TESS satellite found patterns which can help us learn more about the inner workings of stars.

Posted: May 16, 2020 12:50 PM
Updated: May 16, 2020 12:50 PM

Stars may appear bright to us on Earth, but peering inside their hearts is a little more elusive. Star data from NASA's planet-hunting TESS mission has helped an international team of scientists detect patterns in 60 pulsating stars.

This data revealed the internal structures of the stars, which could aid in the understanding of what's happening in billions of stars across the universe.

Essentially, the researchers could listen in to the heartbeats of the stars, which created a kind of music. The study published Wednesday in the journal Nature.

This particular class of stars are known as the Delta Scuti stars. They get their name from a bright star, Delta Scuti, in the Scutum constellations and they're each about 1.5 to 2.5 times the mass of our sun.

Previously, astronomers were able to detect pulsations in these stars, but they couldn't determine a pattern.

Pulsations are natural resonances that come from the stars, formed by trapped waves similar to those in musical instruments. These sound waves travel from within the star to create pulsation patterns at their surfaces. To astronomers, these appear as changes in the star's brightness.

A pulsating mystery

When stars pulsate astronomers can learn key details about them.

These movements back and forth inside of stars, called oscillations, can reveal their inner workings. This is called asteroseismology, which is when we learn more about stars by measured changes in the star's light.

It's similar to how earthquakes allow us to study Earth's interior in seismology.

For example, the changes in brightness of our sun have provided astronomers with information about its temperature and chemical makeup, as well as the processes occurring inside it.

Asteroseismology has been used to understand stars like our sun, high-mass stars, red giants and white dwarfs. But Delta Scuti stars confounded scientists until now.

This is because while "many stars pulsate along simple chords," the tune of the Delta Scuti stars is much more complex, said Tim Bedding, lead study author and professor at the University of Sydney, in a statement.

Delta Scuti stars rotate once or twice a day, which is much quicker, and about a dozen times faster, than our sun. That can shake up the pulsation patterns and make them difficult to interpret.

"The signals from these stars have been a mystery for over a hundred years," said Daniel Huber, study co-author and assistant professor at the University of Hawaii's Institute for Astronomy. "We knew that brightness variations in these stars are caused by sound waves traveling in their interior, but we just couldn't make any sense of them."

The TESS mission, which was designed to detect exoplanets, or planets outside of our solar system, around nearby stars, captures data about star brightness. When astronomers used TESS data, they could narrow their focus to 60 Delta Scuti stars, between 60 to 1,400 light-years away from Earth, with clear pulsations in brightness. These regularly pulsed with high frequency.

The TESS data needed to be processed through software, which was designed by Daniel Hey, study co-author and a doctoral student at the University of Sydney.

"We needed to process all 92,000 light curves, which measure a star's brightness over time," Hey said in a statement.

"From here we had to cut through the noise, leaving us with the clear patterns of the 60 stars identified in the study. Using the open-source Python library, Lightkurve, we managed to process all of the light curve data on my university desktop computer in a just few days."

Observations from the W. M. Keck Observatory on Maunakea in Hawaii also revealed that the regular patterns came from Delta Scutti stars that were spinning slower than normal, which could help explain their frequency patterns. Follow-up observations were also conducted using the global Las Cumbres Observatory network.

Listening to celestial heartbeats

"Previously we were finding too many jumbled up notes to understand these pulsating stars properly," Bedding said.

"It was a mess, like listening to a cat walking on a piano. The incredibly precise data from NASA's TESS mission have allowed us to cut through the noise. Now we can detect structure, more like listening to nice chords being played on the piano."

Huber compared it to "notes of a song finally falling into place to play a beautiful melody."

And pulsations by Delta Scuti stars can reveal their mass, age and internal structure.

"Our results show that this class of stars is very young and some tend to hang around in loose associations. They haven't got the idea of 'social distancing' rules yet," Bedding said.

Young stars allow astronomers the chance to see how stars evolve, as well as the formation and evolution of planets around them -- kind of like peering back into the formation of our own solar system, said Eric Gaidos, study co-author and professor in the University of Hawaii's School of Ocean and Earth Science and Technology.

"Some of the stars in our sample host planets, including beta Pictoris, just 60 light years from Earth and which is visible to the naked eye from Australia," said Isabel Colman, study co-author and doctoral candidate at the University of Sydney, in a statement. "The more we know about stars, the more we learn about their potential effects on their planets."

It's a breakthrough for the researchers and they plan to continue observing Delta Scuti stars with TESS going forward. Although TESS was designed to find exoplanets, there were also hopes that it could help advance asteroseismology -- and it's just getting started.

"We are thrilled that TESS data is being used by astronomers throughout the world to deepen our knowledge of stellar processes," said George Ricker, study co-author and TESS Principal Investigator at the Massachusetts Institute of Technology's Kavli Institute for Astrophysics and Space Research in Cambridge, in a statement.

"The findings have opened up entirely new horizons for better understanding a whole class of stars."

Indiana Coronavirus Cases

Data is updated nightly.

Confirmed Cases: 75862

Reported Deaths: 3069
CountyConfirmedDeaths
Marion16088730
Lake7688278
Elkhart492685
Allen4002163
St. Joseph357883
Hamilton2829104
Vanderburgh202213
Hendricks1927108
Cass18029
Johnson1789119
Porter135539
Clark128749
Tippecanoe123811
Madison100665
LaPorte93130
Howard91365
Kosciusko86812
Bartholomew81747
Floyd80948
Marshall79323
Monroe76631
Delaware74552
Dubois70812
Vigo69911
Noble68829
Boone68746
Hancock68339
Jackson5965
Warrick58830
Shelby56527
LaGrange56310
Grant52930
Dearborn51228
Morgan49334
Clinton4444
Henry40620
Wayne38510
White37611
Montgomery35921
Lawrence35227
Harrison34823
Decatur34132
Putnam3128
Daviess27720
Miami2772
Scott27210
Jasper2552
Greene25434
Franklin24615
DeKalb2384
Gibson2314
Jennings22712
Steuben2133
Ripley2138
Carroll1962
Fayette1947
Perry18713
Posey1790
Starke1787
Wells1742
Orange17424
Fulton1722
Wabash1703
Jefferson1672
Knox1610
Whitley1556
Tipton14312
Washington1421
Sullivan1381
Spencer1373
Clay1245
Huntington1243
Randolph1244
Newton12010
Adams1092
Owen991
Jay920
Rush854
Pulaski811
Fountain742
Brown741
Blackford652
Ohio656
Benton640
Pike590
Vermillion580
Switzerland530
Parke511
Martin480
Crawford450
Union410
Warren241
Unassigned0206

Ohio Coronavirus Cases

Data is updated nightly.

Confirmed Cases: 102826

Reported Deaths: 3708
CountyConfirmedDeaths
Franklin18697529
Cuyahoga13734505
Hamilton9766257
Lucas5448326
Montgomery443896
Summit3614223
Butler297663
Marion293545
Mahoning2595255
Pickaway239142
Stark1884140
Warren182139
Lorain181377
Columbiana167160
Trumbull1549108
Fairfield141632
Delaware134419
Licking131951
Clark117815
Lake113141
Wood106858
Clermont95311
Medina94535
Miami85839
Tuscarawas79314
Portage77163
Allen76946
Greene71812
Mercer63113
Belmont62326
Richland61412
Erie59728
Ashtabula57646
Geauga55944
Wayne54558
Ross4944
Darke40629
Huron4045
Madison40110
Ottawa39626
Sandusky39017
Hancock3893
Athens3602
Holmes3286
Lawrence3000
Auglaize2636
Union2601
Muskingum2431
Scioto2421
Jefferson2373
Seneca2283
Knox2127
Putnam21117
Shelby2104
Washington20922
Preble2072
Coshocton1967
Champaign1812
Morrow1762
Crawford1755
Hardin17012
Clinton1696
Highland1661
Logan1602
Ashland1543
Fulton1531
Wyandot1509
Defiance1504
Brown1462
Perry1403
Williams1363
Henry1222
Fayette1210
Guernsey1197
Hocking1189
Carroll1135
Monroe9418
Pike790
Jackson760
Van Wert732
Paulding700
Gallia701
Adams612
Meigs540
Vinton322
Morgan300
Harrison261
Noble160
Unassigned00
Fort Wayne
Clear
84° wxIcon
Hi: 82° Lo: 56°
Feels Like: 84°
Angola
Clear
81° wxIcon
Hi: 82° Lo: 57°
Feels Like: 81°
Huntington
Broken Clouds
82° wxIcon
Hi: 82° Lo: 58°
Feels Like: 83°
Decatur
Scattered Clouds
81° wxIcon
Hi: 82° Lo: 56°
Feels Like: 81°
Van Wert
Scattered Clouds
81° wxIcon
Hi: 83° Lo: 56°
Feels Like: 81°
Mostly Sunny Thursday
WFFT Radar
WFFT Temperatures
WFFT National

Community Events