André Beaudoin, an iREx Masters student, completed his M.Sc. at Université de Montréal in 2023. Here, he summarizes his Masters research project.
“Are we alone in the Universe” is perhaps the most important fundamental question in modern astrophysics. But how can we answer it? And what astronomical instruments will be needed to find the answer?
The most promising avenue is the search for biosignatures, i.e. chemical elements or molecules that cannot exist – or coexist – without the presence of life on an exoplanet. A classic biosignature is the dioxygen-methane molecule pair. This pair has only been observed on Earth, and it seems impossible to maintain a significant concentration of both molecules simultaneously on a planet without the presence of life to regenerate them. The detection of these two molecules on an Earth-like exoplanet would be a phenomenal breakthrough in the search for life elsewhere in the Universe. This brings us to the second question: what kind of astronomical instrument will it take to detect these molecules?
Today’s state-of-the-art instruments, such as the James Webb Space Telescope, are capable of detecting the presence of certain chemical elements on some exoplanets, but it remains a great challenge to study Earth-sized exoplanets with these instruments. Moreover, the detection of oxygen remains elusive, given the difficulties specifically linked to its detection. The next generation of telescopes, the so-called giant telescopes, will push back the frontiers of what is possible. The largest telescope of this generation, the Extremely Large Telescope (ELT), will have a main mirror 39 metres in diameter, making it the largest optical telescope ever built. It is currently under construction in Chile, and is scheduled to start its operations in 2028.
My master’s project involved evaluating the ELT’s performance, specifically that of one of its instruments, ANDES, for detecting chemical elements in the atmosphere of terrestrial exoplanets. I therefore digitally built a simulator that reproduces the instrument very precisely, in which I included all the modules and as many sources of error as possible. Thanks to this simulator, I’ve been able to assess under which conditions and on which exoplanets it will be possible to detect the chemical elements we’re interested in. In summary, in its current design, the instrument would allow us to detect water on some terrestrial exoplanets, but it would remain very difficult to detect other chemical molecules of interest.
André completed her MSc at UdeM between 2021 and 2023, under the supervision of iREx Director René Doyon. Her thesis will be available soon.