So far, the early history of stars has received little attention in conventional models of stellar evolution. Thomas Steindl of the University of Innsbruck's Department of Astro- and Particle Physics has demonstrated for the first time that the biography of stars is actually affected by their early stage. The findings were reported in the journal Nature Communications.
From newborns to teens, stars in their "young years" provide a significant scientific challenge. In theoretical models, the process of star creation is especially intricate and difficult to trace. Observing the oscillations of stars is one of the few techniques to learn more about their genesis, structure, or age.
According to Konstanze Zwintz, similar to the research of the Earth's interior using seismology, we may similarly draw assertions about the internal structure and consequently the age of stars based on their oscillations.
The astronomer is considered as a pioneer in the nascent area of asteroseismology, and he directs the research group Stellar Evolution and Asteroseismology at the University of Innsbruck's Institute for Astro- and Particle Physics. The study of star oscillations has advanced greatly in recent years due to advances in precision observation using space observatories such as TESS, Kepler, and James Webb. These breakthroughs are also throwing fresh light on long-held ideas of star development.
Stars are referred to as "children" as long as their cores are not yet converting hydrogen to helium. They are in the pre-main sequence at this point; following ignition, they become adults and move on to the main sequence.
According to Thomas Steindl, a member of Konstanze Zwintz's research group and the study's primary author, research on stars has so far concentrated mostly on adult stars such as our sun. Even though it may appear illogical at first, the evolution of the pre-main sequence has received little attention thus far since the period is tumultuous and difficult to describe. Only recent technical developments have allowed us to get a closer look at the infancy of stars, and hence at the point when the star begins to combine hydrogen into helium.
The two Innsbruck researchers have now presented a model that may be used to realistically describe the early stages of a star's existence long before they become adults in their current work. MESA, an open-source stellar evolution tool, serves as the foundation for the model (Modules for Experiments in Stellar Astrophysics). Thomas Steindl spent months perfecting the strategy for utilizing this stellar evolution algorithm to reproduce the chaotic period of early star formation and then anticipate their individual oscillations after being inspired by a discussion delivered by astronomer Eduard Vorobyov of the University of Vienna at a 2019 symposium.
According to Steindl, "our data show that stars on the pre-main sequence evolve in a very chaotic manner." We can now employ it in our new theoretical model, notwithstanding its complexity. Thus, the astronomer demonstrates that the manner a star is produced influences its oscillation behavior even after nuclear fusion is ignited in the main sequence. The star's infancy has an effect on its subsequent pulsations: This seems obvious, yet it was heavily contested. The classical hypothesis holds that the period preceding ignition is meaningless. This is not correct: Similar to a musical instrument, even little modifications in composition result in huge changes in tone. As a result, our newer models more accurately explain the oscillations in actual stars.
According to Konstanze Zwintz, "I was already convinced about 20 years ago, when I first saw the oscillation of a young star in front of me on the screen, that one day I would be able to prove the significance of early stellar evolution on the 'adult' star." We have now succeeded thanks to Thomas Steindl's outstanding work: a true epiphany moment for our research team and another milestone toward a deeper understanding of the stages of star formation.
Journal Information: Thomas Steindl et al, The imprint of star formation on stellar pulsations, Nature Communications (2022). DOI: 10.1038/s41467-022-32882-0