A Planetary Mission

Posted On May 14, 2012 by Jeremy Craig

ATLANTA – Ever since the first planets outside of our solar system were discovered, scientists have been trying to form a theory to explain how they are formed.

It’s a problem that’s not easy to solve, because the first planetary systems outside of our solar system were very different from our own. Gas giant planets, like Jupiter, were found very close to stars, unlike our solar system, where the gas giants are farther away.

Nicole Cabrera is trying to better understand how solar systems form by studying young stars – and hopefully, finding young planets orbiting them.

“Instead of looking at stars that are the age of our sun, I’m looking at younger stars to see what kind of planets we find there,” she said. “If we find the same systems that we’ve been finding – and even if we don’t – we can start putting constraints on the development of systems.”

Cabrera, a Ph.D. student in GSU’s astronomy program, recently received a Graduate Research Fellowship from the National Science Foundation to support her studies and her research.

Working under assistant professor Russel White, Cabrera hopes to find what no one has found before – young planets orbiting young stars. It’s a search that will be difficult.

“There have been groups who have claimed to find young planets, but have been disproved. It’s very difficult to observe young stars because they’re so volatile and the technology just hasn’t been there until now,” she said.

But even the examination of young stars will help yield new knowledge to help astronomers in the future.

“Finding a young planet would be cutting edge, but even if we don’t find one, just looking at these young stars and finding out about their properties and how they behave will lay very important groundwork for the future,” Cabrera said.

In the search for young planets, Cabrera is using spectroscopy to analyze the light coming from a star. Scientists can’t visually observe planets outside of our solar system – or “exoplanets” – so they spread light from the stars out, just as light is separated into different colors using a prism.

“We look at the little features, the absorption lines you would see from the star,” Cabrera explained. “If it is a normal star, all of these features should be in the same place all of time. But if there’s a planet going around the star, the absorption features will shift back and forth due to the gravitation of the planet pulling on either side of the star.”

Cabrera, whose family moved to the United States from Chile when she was 2, said that she’s always found science interesting, and eventually came around to looking towards physics as a field of study.

“I thought about a career in astrophysics,” she said. “I really didn’t know at that point what I wanted to do, but I had a little bit of guidance.”

She made her way from the Miami, Fla., area to Georgia Tech where she chose a rigorous research path by joining a project modeling eclipsing binary stars using computers.

“It was my first true research project. As an undergrad in my junior year, I had never taken a programming class before, or even worked with a terminal,” Cabrera said. “I had to learn everything from scratch.”

In 2010, after completing two NSF astronomy research internships, she continued onto graduate school.

She said she picked the Georgia State astronomy program because she liked how GSU’s department differed from others across the country.

“Everyone’s on a first name basis,” Cabrera said. “Graduate students are more peers of the faculty than anything else. That’s a huge difference from many other schools, where students are competing against each other and the faculty are at different levels from them.”

She said that after completing her Ph.D., she hopes to become a professor and researcher, but first she would like to go to France as a post-doctoral fellow at a scientific or academic institution there.

“Part of my current thesis project will be conducted in France. I feel like I can make some connections there,” Cabrera said. “I think it will be really important to get a different perspective for my research.”

May 14, 2012