Childhood of stars shapes stellar evolution

    Scientists now show that the biography of stars is indeed shaped by their early stage.
    By: ANI
    | Updated on: Sep 21 2022, 22:59 IST
    STUNNING image of Tarantula Nebula captured by THIS reveolutionary telescope
    Tarantula Nebula
    1/5 The stunning image was captured by scientists using the data collected via the revolutionary Atacama Large Millimeter/submillimeter Array (ALMA) telescope located in the Antofagasta Region of the Atacama Desert in Chile. (REUTERS)
    NASA
    2/5 The Tarantula Nebula is present at the center of the Large Magellanic Cloud, a satellite galaxy of the Milky Way system and has given birth to more than 800,000 stars, some of them nearly 150 times the size of the Sun. This makes the Tarantula Nebula one of the prime observation destinations for researchers and science buffs alike. (NASA)
    Tarantula Nebula
    3/5 "What makes 30 Doradus unique is that it is close enough for us to study in detail how stars are forming, and yet its properties are similar to those found in very distant galaxies when the Universe was young,” said European Space Agency (ESA) scientist Guido De Marchi. "Thanks to 30 Doradus, we can study how stars used to form 10 billion years ago, when most stars were born." He added further. (NASA/Hubble)
    Tarantula Nebula
    4/5 The 30 Doradus is also called the Tarantula Nebula because of its glowing filaments which resemble spider legs, according to NASA. The Nebula is special as it can be seen in the Southern sky with the naked eye. It resembles a large milky patch of stars when viewed from Earth. (NASA/ESA)
    Hidden Galaxy
    5/5 The findings of the observation state that gravity is still responsible for the formation of the milky way galaxy and it is still shaping up the galaxy, which has aided in the continuous formation of stars. Tony Wong, a professor from the Astronomy Department at the University of Illinois said, "Our results imply that even in the presence of very strong feedback, gravity can exert a strong influence and lead to a continuation of star formation.” (NASA)
    Nebula
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    From babies to teenagers: stars in their "young years" are a major challenge for science. (AFP)

    In classical models of stellar evolution, so far little importance has been attached to the early evolution of stars. Scientists now show that the biography of stars is indeed shaped by their early stage.

    From babies to teenagers: stars in their "young years" are a major challenge for science. The process of star formation is particularly complex and difficult to map in theoretical models. One of the few ways to learn more about the formation, structure or age of stars is to observe their oscillations. "Comparable to the exploration of the Earth's interior with the help of seismology, we can also make statements about their internal structure and thus also about the age of stars based on their oscillations" says Konstanze Zwintz. The astronomer is regarded as a pioneer in the young field of asteroseismology and heads the research group "Stellar Evolution and Asteroseismology" at the Institute for Astro- and Particle Physics at the University of Innsbruck. The study of stellar oscillations has evolved significantly in recent years because the possibilities for precise observation through telescopes in space such as TESS, Kepler, and James Webb have improved on many levels. These advances are now also shedding new light on decades-old theories of stellar evolution.

    Stars are called "children" as long as they are not yet burning hydrogen to helium in their cores. At this stage, they are on the pre-main sequence; after ignition, they become adults and move onto the main sequence. "Research on stars has so far focused mainly on adult stars -- such as our Sun" says Thomas Steindl, a member of Konstanze Zwintz's research group and lead author of the study. "Even if it sounds counterintuitive at first glance, so far little attention has been paid to the evolution of the pre-main sequence because the phase is very turbulent and difficult to model. It's only the technological advances of recent years that allow us a closer look at the infancy of stars -- and thus at that moment when the star begins to fuse hydrogen into helium." In their current study, the two Innsbruck researchers now present a model that can be used to realistically depict the earliest phases of a star's life long before they become adults. The model is based on the open-source stellar evolution program MESA (Modules for Experiments in Stellar Astrophysics).

    Inspired by a talk given by astronomer Eduard Vorobyov of the University of Vienna at a 2019 meeting, Thomas Steindl spent months refining the method for using this stellar evolution code to recreate the chaotic phase of early star formation and then predict their specific oscillations. "Our data show that stars on the pre-main sequence take a very chaotic course in their evolution. Despite its complexity, we can now use it in our new theoretical model." Steindl said. Thus, the astronomer shows that the way the star is formed has an impact on the oscillation behaviour even after ignition of nuclear fusion on the main sequence: "The infancy has an influence on the later pulsations of the star: This sounds very simple, but it was strongly in doubt. The classical theory assumes that the time before ignition is simply irrelevant. This is not true: Comparable to a musical instrument, even subtle differences in the composition lead to significant changes in the tone. Thus, our modern models better describe the oscillations in real stars."

    Konstanze Zwintz is delighted with this discovery and is very optimistic about the future: "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 I would one day be able to prove the significance of early stellar evolution on the 'adult' star. Thanks to the great work of Thomas Steindl, we have now succeeded: Definitely a eureka moment for our research group and another milestone for a better understanding of the growth steps of stars.

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    First Published Date: 21 Sep, 22:59 IST
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