Star Search

Catrina Hamilton-Drager probes deep space for clues to planetary origins

by Bill Sulon

November 10, 2009

Catrina Hamilton-Drager, assistant professor of physics and astronomy, is searching deep space for clues to the origin of planets.

Catrina Hamilton-Drager was 5 when she hopped off her swingset, looked up and gazed at her future.
“I was astounded by what I saw,” she said. “I laid down on the ground and stayed there, looking up. My mom came out to get me because she thought I was hurt.”

The sun had set on the warm summer night at her home in Irondequoit, a suburb of Rochester, N.Y. As the sky darkened, her eyes widened.

The stars that mesmerized her as a child have an even stronger pull today, thanks to encouraging parents who nurtured her curiosity with astronomy books and a telescope, and despite a discouraging high-school teacher who suggested that, because of her gender, she set her career sights elsewhere.

Hamilton-Drager, assistant professor of physics and astronomy, is focusing her attention and much bigger telescopes 2,400 lights years away on two stars orbiting each other, surrounded by a ring of rocks, dust and other interstellar particles named KH 15D.

‘Winking star’

The so-called protoplanetary disk barely registers as a dot through the powerful Hubble space telescope, and massive telescopes in Hawaii and Arizona. But the rhythmic waning and brightening of that dot, also dubbed the “winking star,” is helping Hamilton-Drager and other astronomers better understand what they hypothesize to be the adolescent stage of planet formation.

The winks are eclipses that occur when the stars orbit each other and pop up over what is believed to be a surrounding disk of gas, dust and rocks. The disk appears to be growing denser.

“We believe that this is a transitional disk,” Hamilton-Drager said. “We theorize that they go through this process, but it has rarely been observed.”

A student at Wesleyan University made the initial observation of the anomaly in 1995. Hamilton-Drager, who earned a master’s degree from Arizona State University, attended Wesleyan and turned KH 15D into a Ph.D. project. She earned her doctorate in 2003 and three years later came to Dickinson, where she continues her research of the system.

“It’s something I plan to keep doing over my lifetime,” she said.

The research entails monitoring KH 15D using the latest advances in astronomy technology, including an infrared telescope and writing research papers on different aspects of KH 15D. The goal is to unlock more mysteries about KH 15D and accumulate more evidence that it is in the early phase of becoming a solar system with fledgling planets.

“So is KH 15D the Rosetta stone–is it the key?” Hamilton-Drager asked. “It may not be the key, but I think it is very important for understanding the physics of the formation of planets.”

When not teaching, researching KH 15D or searching the skies for other astral wonders, Hamilton-Drager works with three seniors—Mara Anderson, Eric Dornbush and Kelly Maurer—on separate projects. Anderson is setting up and testing a new spectrometer, which measures properties of light, on the telescope in the Michael L. Britton Memorial Observatory at the Rector Science Complex. Dornbush is using the telescope to observe a suspected supernova progenitor, or exploding star. And Maurer is using the telescope to search for transiting planets around other stars.

Working with students reminds Hamilton-Drager of her early days of space exploration. At age 11, six years after her swingset epiphany, she and her father observed a light streak across the sky. It was a satellite. “It was really exciting for me,” she said.

High aspirations

That excitement continued through high school until her senior year, when a teacher asked the students to name their college choices as well as their planned field of study. Hamilton-Drager wasn’t sure where she wanted to go to college, but she was certain of her major.

She eagerly told the teacher and her classmates, “I want to be an astronomer.”

The teacher paused, then said slowly, “You might want to consider another field. Astronomy is male-dominated.”

“I was mortified,” Hamilton-Drager said.

But not dissuaded. Around that time, she received a brochure from Mount Holyoke College, a liberal-arts college for women.

“I figured nobody there was going to tell me I couldn’t study astronomy,” Hamilton-Drager said.

Nobody did. Hamilton enrolled at Mount Holyoke, where she designed a special major for herself. In 1991 she earned a bachelor’s degree in astrophysics.

Hamilton-Drager is doing all in her power to open doors for other women who want to pursue careers in astronomy, and she isn’t waiting until they reach high school to address the issue. At home in Newville, Pa., Hamilton-Drager’s daughter, 2-year-old Olivia “Livi” gets to gaze at a lamp-generated light show of planets and stars while getting her diaper changed.

“A few of her first words were galaxy, Einstein and Newton,” Hamilton-Drager said proudly.