The DTU researchers contributed to an international study that was able to detect and map the elusive pulse patterns for 60 large young stars that, until now, were difficult to study. The results were published in the journal Nature.
Using observations from NASA’s TESS spacecraft, an international research group involving researchers from DTU Space and the Stellar Astrophysics Center at Aarhus University was able to detect and map elusive pulse patterns for 60 stars, called Delta Scuti stars, which so far have been difficult to study.
This discovery will revolutionize the ability of scientists to study details such as the age, size and composition of these types of stars – all members of a class named after the bright star Delta Scuti.
It is for the first time that such systematic patterns have been identified in a significant number of stars. These results have now been published in the renowned scientific journal Nature.
“These new results are both amazing and important, we can finally see the forest for the trees and perform detailed analyzes of these stars and study the aspects that have eluded us for 120 years, since the discovery of the prototype. We will be able to characterize in detail the interior of these stars and to study with precision the mechanism supporting these pulsations ”, explains Victoria Antoci, astrophysis and principal researcher at DTU Space, co-author of the article published in Nature.
The 60 stars belong to a class of variable stars named after Delta Scuti, a star visible to the human eye in the constellation of South Scutum which was first identified as variable in 1900. Since then, astronomers have identified thousands of others as Delta Scuti.
Victoria Antoci, principal investigator at DTU Space
Younger than the sun, but taller
Delta Scuti stars, in general, have a mass 1.5-2 times greater than that of the sun and are believed to be younger than about 1.5-2 billion years.
However, the sample of 60 stars observed here are all younger than about 500 million years old, many of them are less than 200 years old – in comparison, the Sun is 4.6 billion years old.
On average, they revolve around their axis about 1-2 times a day, which is 30 to 60 times faster than the sun, making it difficult to decipher their pulse patterns, which are essential for better knowledge of the ‘star.
“The Delta Scuti stars are clearly pulsating in an interesting way, but the patterns of these pulses have so far defied understanding,” says the lead author of the article in Nature, cooperating University professor Sydney Bed Tim with the Stellar Astrophysics Center at the University of Aarhus. .
“To use a musical analogy, many stars pulse along simple chords, but the Delta Scuti stars are complex, with notes that seem to be mixed. TESS has shown us that this is not true for everyone. “
Delta Scuti stars have been frustrating targets for scientists due to their complicated oscillations. Being able to find simple patterns and identify patterns of oscillation is a game-changer.
Now scientists have a regular series of pulses for these stars that can be compared to models, resulting in an accurate age determination that is otherwise difficult to obtain. This will allow them to measure these stars much more effectively using asteroseismology, in principle in the same way that seismologists study the Earth by analyzing the movements on its surface to gain knowledge about its interior.
Understanding the astrophysical phenomena operating in Delta Scuti stars could even provide new information on the functioning of the Sun and why it is a relatively stable and calm star.
Full involvement of the DTU space
The discoveries were made using data from TESS, a NASA Astrophysics Explorer mission launched in 2018 and directed and operated by MIT and managed by NASA’s Goddard Space Flight Center.
DTU Space is also involved in the TESS mission, having provided the star tracking system used for spacecraft navigation and being part of the TESS scientific team which mainly works on the discovery and characterization of thousands of exoplanets around of bright stars close by.