La Grande conférence 2025: Cold Worlds

Artistic representation of a young brown dwarf. Credit: NASA/JPL-Caltech.
Artistic representation of a young brown dwarf. Credit: NASA/JPL-Caltech.

What is a brown dwarf? How can these celestial objects help us understand planets and the universe? And how is the James Webb Space Telescope unlocking new insights into their unique chemistry? 

Join us for “Cold Worlds Revealed by the James Webb Space Telescope,” the 2025 edition of the Grande conférence de l’IREx, on March 27, 2025, at 7 p.m., to explore these fascinating cold worlds. The lecture, presented in English by Jackie Faherty, senior scientist and senior education manager at the American Museum of Natural History (AMNH) in New York, will take you on an exciting journey into some of the coolest worlds in our universe.

This event will take place at the Université de Montréal’s campus MIL (1375 Av. Thérèse-Lavoie-Roux, Montréal, QC, H2V 0B3) in Amphitheater A3502.1 (3rd floor).

Admission is free, but seating is limited, so arrive early! The lecture will start at 7:00p.m.

Can’t make it in person? The conference will also be broadcast live online on our social media channels, thanks to our precious partner, AstroPoly :

No prior knowledge of science or astronomy is needed—this talk is designed for everyone interested in space and science. Feel free to invite your family, friends, and colleagues to join you. We’ll soon post the Facebook event so you can easily share it!

Summary

Beyond our solar system, there are worlds that are now revealed by the James Webb Space Telescope (JWST), a powerful telescope launched into space in 2021. Among them, brown dwarfs are a key class of objects, just a little more massive than planets. They have been trailblazing our understanding of the diversity of atmospheric compositions for giant exoplanets. In this talk, I will show a diversity of observations obtained using JWST on brown dwarfs with temperatures that range from ~425°C all the way down to -25°C, temperatures barely warmer than Jupiter. The light of these brown dwarfs can be analysed to reveal their complex chemistry and key molecules in their atmospheres. While we initially theorized that their temperature would primarily influence the sort of composition of these worlds, JWST reveals a far more intricate landscape where other parameters like age, metallicity, and gravity strongly influence what we see.

Our Speaker

Jackie Faherty is a senior scientist and education manager at the American Museum of Natural History (AMNH) of New York, United States. Her research group entitled “Brown Dwarfs in New York City (BDNYC)” is at the forefront of low mass star, brown dwarf and giant exoplanet characterization studies.  She has co-founded the popular citizen science project entitled Backyard Worlds:  Planet 9 which invites the general public to help scan the solar neighborhood for previously missed cold worlds. Faherty has over 180 peer reviewed articles in Astrophysical journals, has been an invited speaker at University’s and conferences across the globe and is a major advocate for utilizing visualization tools for both science and education advancements.  Aside from a love of scientific research, Dr. Faherty is a passionate educator and can often be found giving public lectures in the Hayden Planetarium.  She holds a unique position at the American Museum of Natural History that allows her to pursue scientific research at the forefront of exoplanet characterization studies while mentoring and advising education programs for students and general public alike.