Olivia Gaunt’s Reach for the Stars

This astronomy graduate student leads high schoolers in researching rare stellar formations

When Olivia Gaunt was an undergraduate at Wellesley College, she studied physics, but it wasn’t until her senior year that she figured out what she’d do with it. A visit to the Goddard Space Flight Center in Maryland pointed her in the direction she soon decided on: astrophysics.

Now in her third year of a Ph.D. program in the physics and astronomy department, Gaunt is focused on studying the evolution of galaxies, working with Associate Professor Anna Sajina. A few years ago, in the midst of the pandemic, she was looking for a side project, and came across the Science Internship Program. She began working with University of California Santa Cruz astronomy professor Puragra (Raja) GuhaThakurta in leading high schoolers from around the world in a series of summer astronomy research projects.

This summer she presented findings from the latest project at the 242nd meeting of the American Astronomical Society on a rare type of star that her team is tracking, meriting a write-up on Space.com.

Who’s involved with you on the project?

It’s me and my little team of high schoolers, who switch out every summer. They’re from everywhere—a lot from California, but it’s international. This year I have two students from Turkey, one of whom has traveled to meet me in person at UC Santa Cruz, when I was on campus for a week. We’ve had others from the East Coast, India, and China.

What has your group been researching?

We used a huge stellar survey of stars in the Triangulum galaxy. We focused on strange stellar objects that didn’t look how we expected them to look. They had very broad emission lines that show up as visible light and some really interesting shapes. We found six of them, which we called BELLS, for broad emission-lined luminous sources.

We’ve been able to get some follow-up survey spectra of these objects—we have 2018 and 2022 data for three of them. They looked weird in the 2018 data, and we wondered if they still looked weird four years later. We want to identify as many of these objects in the dataset as we can, thoroughly cataloging the emission features and seeing if we can describe them in a way that’s meaningful and measure anything useful from them. We’ve been working this summer on categorizing the differences and comparing them.

Did you come to any conclusions about the stars you were watching?

We’ve decided these BELLS are Wolf-Rayet stars. It’s not what we were expecting. Wolf-Rayet stars are super rare and not well studied. Wolf-Rayet is a phase in the life of massive stars, but there are very few of these objects. They’re so rare that we think they may exist only for a short amount of time—in astronomy there’s a connection between rarity and timescale.

A woman looks to her left at a bright object

Photo: Alonso Nichols

I’m hoping that we’ll see that something going on with the stars has changed over the four years and that they are emitting a different emission line than they were before. That would indicate some sort of evolution within the Wolf-Rayet lifetime.

The other thing about these stars is they’re not cut and dry Wolf-Rayet stars. There’s something in between—there’s a transition phase between when it’s a bright star and a Wolf-Rayet star. We think they’re transitioning into Wolf Rayet-hood, if you will.

How have the high school students reacted to the project?

The summer program is over, and I’ve already heard from several of them that they’d like to continue working on the project throughout the year. They all expressed interest in what the new data we’re expecting in the fall will show, and have asked for updates. It’s clear to me that they have fostered a sense of curiosity and wonder about space. I’ve also absolutely kept in touch with students from past years—they’ll often reach out, and some even want to return to the project after a year or two. They have been so excited about this work.

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