Research & Discovery

A Star Is Born: UVA Undergrad Leads Team Studying Stellar Formation

December 1, 2023 • By Lorenzo Perez, ljp2h@virginia.edu Lorenzo Perez, ljp2h@virginia.edu

Zoom in on the Sagittarius C, a section of the Milky Way

A UVA undergraduate and his team got a special peek at a segment of space known for star formation, courtesy of the James Webb Space Telescope. The red flaring mass encircled by blue in the image represents an area where a star is forming. (Image courtesy of NASA, ESA, CSA, STScI, Samuel Crowe (UVA))

For most of us on Earth, Sagittarius is simply the constellation that some see in the shape of an archer drawing a bow. But viewed from space through NASA’s James Webb Space Telescope, the region holds a secret of the universe that is also stunningly beautiful: how a star is formed.

NASA released last week some of the eye-popping images of Sagittarius C, a star-forming region at the center of our Milky Way galaxy. The images include what astronomers describe as a “bonfire” of stellar formation activity.

Third-year University of Virginia student Sam Crowe is leading a team of researchers studying that nascent fire to better understand how stars generate.

“I felt like a kid on Christmas when I first downloaded and opened the images on my laptop,” Crowe said. “I was struck by how many stars were in the image – about half a million – and just the overall structure. In terms of physical scale, the entire image is enormous, about 45 light years across. It’s a wide vista, rather than just a zoom in on one particular object.”

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His team is poring over infrared-light images from the telescope and other data from the extreme environment, captured during the September observation window.

“There’s never been any infrared data on this region with the level of resolution and sensitivity we get with Webb, so we are seeing lots of features here for the first time,” Crowe said.

Crowe, who is majoring in astrophysics and history, was able to earn coveted time on the telescope as part of Webb’s General Observer program. He’s believed to be the first undergraduate student to lead research through the program. “The idea of leading a James Webb proposal as an undergraduate student seemed totally absurd, at least in my head,” said Crowe, who attends UVA on a full-tuition University Achievement Award as an Echols and Robert Kent Gooch Scholar.

Sam Crowe is a third-year student majoring in astrophysics and history. (Photo by Evan Kutsko, The College Foundation)

But the more he consulted with professional astronomers, the more it seemed possible. He crafted the proposal in conjunction with Jonathan Tan, his Department of Astronomy adviser; UVA postdoctoral researcher Yichen Zhang; and Rubén Fedriani, a postdoctoral researcher at Spain’s Instituto de Astrofísica de Andalucía.

Crowe now oversees an international research team featuring 13 astronomers from observatories and universities in Spain, Sweden and Japan, as well as UVA and the University of Texas.

He remembers attending the UVA-North Carolina State University football game on Sept. 22 with his girlfriend, looking up at the sky from his seat in Scott Stadium and thinking, “Well, there should be a big telescope pointed at my region right now, taking data, assuming everything goes right.”

At about 10 p.m., Crowe started receiving emails from NASA confirming the capture of imaging data that allows the team to measure how bright each budding star is at different wavelengths.

Their work also includes zooming in on one particularly massive star in the Sagittarius C molecular cloud, designated as “G359.44-0.102.”

Sagittarius C, a section of the Milky Way

This full view of Sagittarius C from the James Webb Space Telescope’s NIRCam (Near-Infrared Camera) instrument, which was taken during Crowe’s observation window, reveals a 50 light-years-wide portion of the Milky Way’s dense center. An estimated 500,000 stars shine, along with some as-yet-unidentified features. (Contributed image)

In addition, the telescope images reveal dusty infrared-dark clouds of interstellar gas that are the sites of future star formation, and a mist of ionized hydrogen excited by radiation from massive stars.

Collectively, the research may soon offer lessons on the flows of matter and energy that control how galaxies evolve.

The team plans on presenting its initial scientific results in January at the American Astronomical Society conference in New Orleans.

“The galactic center is the most extreme environment in our Milky Way galaxy, where current theories of star formation can be put to their most rigorous test,” Tan explained. “It’s great that we’re collecting state-of-the-art data with this fantastic telescope. It’s even more amazing that it’s being led by one of UVA’s best undergrads.”