Reaching for the Stars

Kate Saltovets researches the evolution of the galaxy by plotting the paths of stars—and her future.

Most of us look into the night sky and see the moon and a few stars, or maybe even a meteor shower if the timing is right. (The Perseids are active in July and August). But Lehigh University first-year physics student Kate Saltovets takes her stargazing to a higher level.

Kate has spent this summer working on an independent research project under the mentorship of Associate Professor of Physics Ginny McSwain. Like McSwain, Kate works with space imagery, investigating clusters of stars. Her work benefits from Gaia, a space observatory launched in 2013 by the European Space Agency. Gaia’s mission is to measure the positions and motions of stars, planets, asteroids, and other objects in space with incredible precision in order to build a vast 3D map of the Milky Way. The Gaia project releases publicly available images every few years; the first was in 2016 and the most recent was in 2022. 

Gaia’s images are superior to previous images, with higher resolution and more precise measurements. This lets Earth-bound observers map stars more accurately. Using Gaia and various software programs, she can analyze the age, motion, and energy of stars over time, using cues such as the stars’ color and brightness. Stars are born in the spiral arms of the galaxy, and in images they appear in a group, or cluster. That means they’ve formed together in a “big gas cloud, so they’re usually the same age,” Kate says. She can trace the stars’ movements over time via Gaia’s images. She’s focusing on four clusters in the Cassiopeia region, which hasn’t been thoroughly studied, even before the precise data from Gaia.

While Dr. McSwain’s and Kate’s research projects overlap somewhat, Kate’s research is more independent than directed, and in fact, she’s developed a routine that some full-time researchers might envy: wake up, have some breakfast, work on coding for her research, do her own thing for a while, then code a bit more. Her research lends itself to this kind of immersion and independence. Because she’s working with the most recent data available, there’s no time constraint, and the nature of the investigation lends itself to problem-solving and a kind of follow-your-nose curiosity. This kind of freedom, accompanied by the support of her fellow RARE scholars, is also why she decided to be part of STEM-SI for the summer.

Because researching the galaxy’s history can involve a massive amount of data, some researchers are using machine-learning to plot details. As Kate says, “more and more data are adding up, and with machine learning, I can do it 10 times faster.” But she also sees value in a more manual approach done by a human. Machine learning might miss “interesting cases, like the star is moving somewhere else” than its previous history indicated. Such outliers might be runaway stars or prove not to be part of the initial cluster.

Why study the ages and movements of stars? For Kate, it’s about feeding her inner curiosity, as well as answering fundamental questions about the origin of the universe, both how it began and how it will end. As she says, “we know that the sun will explode and our galaxy will collapse, so we have to think about technology that will let us go somewhere else.” 

Currently a freshman, Kate has established a few goals. First up is quantum computing, which she can take on at Lehigh. As an undergraduate in this field, she’ll be working alongside the advanced undergraduates and graduate students that the program is usually geared to. But she’s eager to find out how its coding capacities can be applied to problems in astrophysics.

This kind of flexible approach to learning was one factor that drew Kate to Lehigh University. She learned about Lehigh through the Ukraine Global Scholars program, which mentors students from Ukraine and helps them find financial aid and scholarships to attend US schools. She investigated the physics department and liked what she saw: small classes that would allow her to make more interpersonal connections with professors as well as make it easier to find a faster path to doing her own research. And after she graduates from Lehigh, she plans to earn a doctorate.

Because of her involvement with Ukraine Global Scholars, Kate will spend five years working in Ukraine when she’s done with school, either for a company or for herself. Because the ongoing war has destroyed labs and other infrastructure, she’s hoping to help rebuild by creating opportunities in STEM for Ukrainian students. She sees it as a way to give back, or maybe to leave her own trace in the evolution of the galaxy.