CUE astrophysics researcher helping chart new cosmic territories

It’s safe to say that the moon is a fairly noticeable figure in the sky, and if you know what to look for, novice stargazers can find Jupiter too. But how would you think to spot Pluto—a tiny fraction the size of Jupiter and millions of times dimmer? 

Pluto is the most famous and largest inhabitant of the Kuiper Belt and modern researchers have discovered thousands of Kuiper Belt objects through the past century. But one problem they continue to explore is whether each of these faint, almost indistinguishable dots in the sky are actually one rock or two.

“That’s a physically interesting question because if it has a binary partner, then nothing crazy has happened to that pair in the intervening billions of years. And that actually tells you a lot about the Solar System’s history,” said Dr. Stephen Portillo, Assistant Professor of Physics at Concordia University of Edmonton (CUE).

Dr. Portillo describes himself as a “prairie stargazer turned astro-statistician” having completed his undergraduate degree in Astrophysics at the University of Alberta before earning a PhD in Astronomy and Astrophysics from Harvard University.

Following his PhD, Dr. Portillo worked at the University of Washington, collaborating with a group of researchers with the DECam Ecliptic Exploration Project (DEEP), an astronomical survey that captured thousands of high-quality images of Kuiper Belt objects. These objects are in the same region of the solar system that Pluto resides in; however, the objects captured were as small as 20 km in diameter—or nearly 120 times smaller than Pluto.

“What are the statistical limits on how much we can learn from these images?” Dr. Portillo asks. “You have this set of data that you might not think you can get information out of because the images are so blurry, but if you throw enough computer time at it with the right algorithms, the information is there. You just have to know how to tease it out.” 

His post-doctoral research has explored both how to develop the right algorithm to tease this information out, and just how much information you can extract. And here at CUE, he’s getting his students involved in this type of research too. 

“This summer, I’m working with one of my students to see how little data we need to ‘rediscover’ Pluto’s moon because that will inform us, when we look at all of these Kuiper Belt objects, if we actually have a shot of finding these binaries with this sort of method,” Dr. Portillo shared. “Another student of mine is trying to answer the question of how close two stars can get before you can no longer tell them apart. And where the rubber hits the road is when you start to use real images to test your algorithms.”

Since arriving at CUE two years ago, Dr. Portillo has found the smaller community here to strike the perfect balance he was looking for as a professor. 

“Around the time I was applying for the position at CUE, I was starting to consider what kind of mix of research and teaching I wanted. And the CUE opportunity was interesting,” he said. 

“The small class sizes have been a lot of fun. I think my favourite course here to teach has been the second semester physics course where we had around a dozen students. I know all of them by name, they’re very active in asking questions in class, using my office hours, and the camaraderie is there with the students, myself, and other instructors.

“That’s been a blast while still being able to keep up with my research.”

Dr. Portillo has done more than just “keep up” with his research. In 2023, he became the first CUE researcher to receive an NSERC grant for physics research. And over the past 12 months, he’s been a co-author on four publications: three in the Astronomical Journal and one in The Planetary Science Journal, supporting the data analysis and statistical measurement side of research that has discovered more than 100 Kuiper Belt objects.

“There are 105 Kuiper Belt objects floating in space that we didn’t know about until my collaborators and I threw a bunch of computer time and images together. That’s just a cool feeling,” said Dr. Portillo. “Now we know slightly more about what’s going on in the solar system than we did before.”