McGill receives funding from the Canadian Space Agency for exoplanet studies using the James Webb Space Telescope

Artist's rendering of SIMP J0136
Image by NASA.
Artist's rendering of LTT 9779b
Published: 13 May 2024

McGill researcher to leverage prodigious capacity of the telescope for studies on a failed star and a hot Neptune-like exoplanet, both with unique stellar characteristics

McGill University announced today it has received funding from the Canadian Space Agency for two separate projects dedicated to the study of exoplanets, using the James Webb Space Telescope (JWST). The projects are slated for completion by June 2025. Both studies will be led by Professor Nicolas Cowan.

Brown dwarves: failed stars

The first study will focus on SIMP J0136+09, the scientific name for a free-floating planet that was discovered using Québec’s very own Observatoire du Mont-Mégantic in the Pisces constellation at a distance of approximately 20 light years from our solar system. Although not technically considered an exoplanet, SIMP J0136 is referred to as a “brown dwarf”, a class of stellar objects that are extremely interesting to astronomers. More massive than gas-giant planets like Jupiter but less so than stars, these substellar objects provide clues as to the formation and evolution of planets.

Professor Cowan will join a team of researchers from the US, UK, and Scotland in the study, which will observe the object using two different instruments on JWST for one full rotation each to provide complete longitudinal information of its atmosphere. Brown dwarfs are relatively new to astronomers, having only been discovered in 1995.

Brown dwarfs are sometimes referred to as ‘failed stars’ as they are capable of fusing the relatively rare isotope deuterium, but not its more abundant cousin, hydrogen. Generally emitting only infrared light, they are easier to observe than other exoplanets, which are often obscured by the light of their host star. In fact, many brown dwarfs are the mass of Jupiter; they are simply free-floating planets. These rogue planets are a valuable test-bed for theories of planet formation, atmospheric dynamics and cloud formation.

Hot Neptune: the planet that shouldn’t exist

The second study will examine the “Hot Neptune” exoplanet LTT 9779b, which is at some 264 light years away from Earth. A recent discovery, having been detected in 2020, this exoplanet is among the most reflective exoplanets known, probably due to a cloudy atmosphere.

This exoplanet is exceedingly hot, at an estimated 2,000°C, so the clouds are likely made of rock or rust. It is possible that the high reflectivity of LTT 9779b explains why the planet exists, as it would keep the planet relatively cool despite the intense radiance of its host star. Indeed, its unique characteristics make it a planet that ‘should not exist,’ according to numerous experts. These counter-intuitive qualities make it a fascinating subject for study.

“If we’re ever going to seriously search for signs of life on exoplanets, we will need to have a very good understanding of all the physical, chemical, and geological processes that occur on these alien worlds,” explained Professor Cowan. “Studying the climate of other planets, even exotic worlds like LTT 9779 b and SIMP J0136, helps us refine our understanding of planetary climates and hence better understand the past, present and future climate of Earth.”

About McGill University

Founded in Montreal, Quebec, in 1821, McGill University is Canada’s top ranked medical doctoral university. McGill is consistently ranked as one of the top universities, both nationally and internationally. It is a world-renowned institution of higher learning with research activities spanning three campuses, 11 faculties, 13 professional schools, 300 programs of study and over 39,000 students, including more than 10,400 graduate students. McGill attracts students from over 150 countries around the world, its 12,000 international students making up 30% of the student body. Over half of McGill students claim a first language other than English, including approximately 20% of our students who say French is their mother tongue.

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