My time at iREx: Daniel Thorngren

Daniel Thorngren, a Trottier Postdoctoral Fellow fellow at Université de Montréal, joined iREx in September 2019. In September 2022, he left iREx to pursue his career as a postdoc at Johns Hopkins University where he’ll be continuing to do exoplanet research. He answered a few of our questions about his time at iREx.

Daniel Thorngren. (Credit: Courtesy Image)

What did you like most about your time in Montreal?

Montreal is a lovely city and it was great to have the new experience of living somewhere bilingual; working with people both at UdeM and at McGill meant that I wasn’t in just one cultural bubble within the city. I also appreciated its emphasis on walkability and public transportation relative to other cities in North America.

What was the most important project(s) you led at iREx?

One of my main focuses at iREx was trying to understand hot Jupiters, both in terms of how the interior connects with the atmosphere (which is more directly observable), and also especially in trying to understand the thermal physics of the planets – how hot their interiors are and why.

What question(s) were you trying to answer in this project?

The big question we’re trying to pick away at is why hot Jupiters are so big – simple physical models don’t predict this, so we must be missing something. Working out how they evolve with time is an important piece of that puzzle, and helps us better model their interiors even before we fully understand the answer.

What did you discover?

We found that hot Jupiters get bigger as their stars brighten with age.  This means that hot Jupiter interiors aren’t just cooling slowly, but are actively heated by their parent star.  This might seem obvious, but while heating an atmosphere is normal and expected, having that heat pushed down into the interior does not follow from our current understanding of planetary physics.  This research helps us narrow down what processes we are missing.

What motivates you in exoplanet research?

I suspect anyone reading this will agree with me that space is just cool, so getting to work on expanding our knowledge of it is very satisfying.  I also particularly enjoy the opportunity to collaborate with people from all over the place on their work, and it’s such an honor when someone asks for my take on a difficult question.

Why do you think people should be interested in this kind of work?

Giant planets are preserved records of the disks that all planets formed from, and understanding them better will help us understand how all planets form, including our own. They’re also the easiest planets to observe, so at any given time we’ll have more and better data to study them with than for terrestrial planets.

How will your time with us help you in your new job?

My work at iREx has led to collaborations with other hot Jupiter experts at JHU and nearby UMD, and my collaborations with Prof Björn Benneke has led me to interface my work better with ongoing atmospheric observations of exoplanets. This is particularly important now that JWST has launched, and we’re already quite busy interpreting that data!