Understanding the inner workings of the stars [Sponsored]

This podcast was produced for the Kavli Prize by Scientific American Custom Media, a separate division of the magazine’s Board of Editors.

Megan Hall: We know that stars shine at night, but what’s going on inside those balls of gas? Connie Aerts uses notes and complex math to answer this question.

He shares the 2022 Kavli Prize in Astrophysics with Jürgen Christensen-Dalsgaard and Roger Ulrich for their work studying pulsating stars to learn more about their inner workings.

Scientific American Custom Media, in partnership with the Kavli Prize, spoke with Conny to learn more about her contribution to this work.

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Hall: Connie Ayarts has spent her life watching the sky.

Connie Ayers: People tell me I still do that today. When I go out of a house or building, I automatically look up.

Hall: It all started when she was a little girl. Her family lived on a remote sandy road devoid of street lights, so she had a great view of the stars.

Arts: So, looking out for me was natural to me when I was a kid. And I was just curious what was going on inside these little dots in the sky.

Hall: I dreamed of being an astronomer.

Arts: But as you know, I’m from a working family. So I had no connection to any cultural life or higher education, let’s say.

Hall: Connie assumed her dream was out of reach. But that all changed after a conversation with the principal of her elementary school. Note that she excelled in mathematics.

Arts: And he really asked, “What do you want to become later?” And so I said, “Well, if I can choose, astronomer, but my mother wants me to be a seamstress. And I don’t like it at all.”

Hall: Her school principal didn’t like that either, so he worked with Connie on a 10-year plan. He even spoke to her mother.

ArtsHe said, “I’m going to convince your mother, I’m going to tell her you’ll be better off in your future, and I’m sure I can convince her to let you go to high school with a lot of math in preparation from college.”

Hall: The plan worked. And after a lot of effort, including a three-hour bus and bike ride to her high school, Connie found herself in a PhD program studying astrophysics. By that time, she had specialized not only in any stars, but in big stars.

Arts: So, my PhD topic was the study of stars whose masses are greater than the Sun. These stars are spinning very fast.

HallTo give you an idea of ​​how fast these stars move, Cooney says our sun takes about a month to make one rotation. The big stars she was studying dart in just one day.

Arts: When a ball of gas is spinning fast, the physics and chemistry are more complex than they are in stars like the Sun, and so I wanted to understand that.

Hall: While she was working on the mystery of how these stars rotate, Connie went to her first academic conference.

Arts: I did not understand much of all the conversations. This is the case when you go to your first conference as a student. But there was a talk by Professor Steve Koller.

Hall: He was studying stars, too. But the technique he used was similar to the way scientists study the depths of the Earth’s interior.

Arts: If we want to know what’s going on deep inside our planet, well, we can’t dig a hole. Because we can’t go deep enough. So, Earth seismologists use earthquakes. Because earthquakes generate waves, and these waves travel inside our planet. It is the tool that a seismologist uses to access the physics and chemistry of the depths of our planet.

HallStars may look like little points in the sky, but they have their own earthquakes, too. As the gas in the star heats up and cools, it causes the surface to pulsate.

Arts: So these small fluctuations give a change in the brightness of the star over time. And by measuring these differences in brightness, we can infer the frequencies of the waves that actually occur inside the star. Because it’s not just the surface, it’s rising and falling globally, the gas.

Hall: This approach is known as stellar science, and a professor at a cosmic conference was using it to understand the rotation of collapsing stars.

Arts: For me, this was an eye opener. I thought, well, I could apply it to my mega stars if I could just get the measurements.

Hall: But that was in the 1990s, before scientists had the tools to monitor stellar earthquakes in space. At the time, seismologists had to measure those pulsations from the ground. It would take at least a decade to gather enough data to understand the waves pulsing inside a massive star. But that didn’t bother Connie.

Arts: I don’t mind having a plan that takes too long. This does not scare me at all. On the contrary, I find it motivating.

Hall: So, when her academic supervisor gave up a star he had been teaching for more than 10 years, Connie kept moving forward.

Arts: Whenever he sent me into the telescope, I would continue to secretly observe this very star. And somehow it did until the telescope was demolished.

Hall: By that time, Kony had 21 years of data on the star. Over the Christmas holidays, I decided to analyze the data. just for fun.

Arts: You see, my work is my hobby. I just love what I do. This is the most fun thing is star analysis. I was analyzing this star after I knew, for sure, that I wouldn’t get any more data with the telescope because the telescope is off. So that was a good moment for me to say, “Well, it’s now or ever for that star.”

Hall: Connie sat upstairs in her living room and began analyzing the data, while her daughter colored downstairs.

Arts: Then suddenly I saw the frequencies.

Hall: not just one frequency. But six. It is enough to know the internal rotation of the star. This has never been done before.

Arts: It was actually the first star, besides the Sun, where we measured the internal rotation rate. That was a breakthrough in our field.

Hall: Connie couldn’t believe it.

Arts: And I was screaming, like, “Wah!” You know, “Why haven’t I seen this before?” You know, because it is, once you spot something, it’s pretty obvious.

Hall: But downstairs, her daughter was unaffected.

Arts: I asked what was going on. Then I tried to explain to her what I found. Then she said, “So what,” you know? [laughs]. She was six years old, you know: “So what? My nerdy mother found something and worked again on her holidays.”

Hall: Her colleagues reacted better. A cosmic research was published in the journal Sciences. It provided a model for finding the internal rotation patterns of other stars.

Arts: We realized as a society, like, OK, we want to do this, not for one star, but for hundreds of stars, because they all rotate differently. But you can’t do 100 times 20 years of waiting, you know?

Hall: So, Kony helped organize a massive data collection initiative.

Arts: Engaging dozens of astronomers around the Earth, sitting on telescopes at different observatories.

Hall: This global project made it possible to avoid some of the data gaps that occur naturally when you are observing a star alone, when daylight obstructs or bad weather conditions. More information speeds up the time it takes to decode it.

Arts: You can do the same research in, you know, not 20 years, but less than two years.

Hall: But the field took an even bigger step forward when those observations moved from Earth to space. Missions like the Kepler space telescope made it possible to study stars that you can’t even see on Earth.

Arts: We had established methods. It was just a matter of getting more data. And then the Kepler mission gave us, like, thousands and thousands of stars with this data.

Hall: Since then, work on seismology has exploded. And be in the middle of it. She co-wrote the first textbook on the field with Don Kurtz and Kavli Prize winner Jürgen Christensen-Dalsgaard. She has also spent time nurturing the next generation of scientists.

Arts: If I can count my master’s, doctoral, and postdoc students, I’ve supervised over 100 of them, which is kind of like a lot.

Hall: But its impact extends far beyond those direct directives. For decades, she has led initiatives to recruit students from diverse backgrounds and bring more women into science.

Arts: For me, this is very important as someone who embeds from the bottom up. That everyone has a chance to contribute.

Hall: She says this drive for diversity probably comes from her own story, when a supportive teacher assistant changed her path from seamstress to scientist.

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HallConnie Aerts is Professor of Astrophysics at KU Leuven in Belgium. This year, she shared the Kavli Prize in Astrophysics with Jürgen Christensen-Dalsgaard and Roger Ulrich.

The Kavli Prize is awarded to scientists for their achievements in astrophysics, nanoscience, and neuroscience — transforming our understanding of the big, the small, and the complex.

The Kavli Prize is a partnership between the Norwegian Academy of Sciences and Letters, the Norwegian Ministry of Education and Research and the US-based Kavli Foundation.

This work was produced by Scientific American Custom Media and made possible through the support of the Kavli Prize.

[The above text is a transcript of this podcast.]

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