From The University of Montréal [Université de Montréal] (CA) : “An extrasolar world covered in water?”
From The University of Montréal [Université de Montréal] (CA)
8.24.22
Marie-Eve Naud
With the help of instruments designed partly in Canada, a team of Université de Montréal astronomers have discovered an exoplanet that could be completely covered in water, a target they hope to observe with the Webb telescope soon.
Artistic rendition of the exoplanet TOI-1452 b, a small planet that may be entirely covered in a deep ocean. Credit: Benoit Gougeon, Université de Montréal.
An international team of researchers led by Charles Cadieux, a Ph.D. student at the Université de Montréal and member of the Institute for Research on Exoplanets (iREx), has announced the discovery of an exoplanet orbiting TOI-1452, one of two small stars in a binary system located in the Draco constellation about 100 light-years from Earth.
The exoplanet, known as TOI-1452 b, is slightly greater in size and mass than Earth and is located at distance from its star where its temperature would be neither too hot nor too cold for liquid water to exist on its surface. The astronomers believe it could be an “ocean planet,” a planet completely covered by a thick layer of water, similar to some of Jupiter’s and Saturn’s moons.
In an article published on August 12th in The Astronomical Journal [below], Cadieux and his team describe the observations that elucidated the nature and characteristics of this unique exoplanet.
“I’m extremely proud of this discovery because it shows the high calibre of our researchers and instrumentation,” said René Doyon, Université de Montréal Professor and Director of iREx and of the Observatoire du Mont-Mégantic (OMM). “It is thanks to the OMM, a special instrument designed in our labs called SPIRou and an innovative analytic method developed by our research team that we were able to detect this one-of-a-kind exoplanet.”
Key role of the Observatoire du Mont-Mégantic
It was NASA’s space telescope TESS, which surveys the entire sky in search of planetary systems similar to our own, that put the researchers on the trail of TOI-1452 b.

Massachusetts Institute of Technology TESS – Transiting Exoplanet Survey Satellite replaced the Kepler Space Telescope in search for exoplanets. TESS is a NASA Astrophysics Explorer mission led and operated by The Massachusetts Institute of Technology, and managed by NASA’s Goddard Space Flight Center.
Based on the TESS signal, which showed a slight decrease in brightness every 11 days, astronomers predicted a planet that has a diameter about 70% larger than that of Earth.
Charles Cadieux belongs to a group of astronomers that does ground follow-up observations of candidates identified by TESS in order to confirm their planet type and characteristics. He uses PESTO, a camera installed on the OMM’s telescope that was developed by Université de Montréal Professor David Lafrenière and his Ph.D. student François-René Lachapelle.
“The OMM played a crucial role in confirming the nature of this signal and estimating the planet’s radius,” explained Cadieux. “This was no routine check. We had to make sure the signal detected by TESS was really caused by an exoplanet circling TOI-1452, the largest of the two stars in that binary system.”
The host star TOI-1452 is much smaller than our Sun and is one of two of similar size stars in a binary system. The two stars orbit each other and are separated by such a small distance — 97 astronomical units, or about two and a half times the distance between the Sun and Pluto — that the TESS telescope sees them as a single point of light. But PESTO’s resolution is high enough to distinguish the two objects, and the images showed that the exoplanet does orbit TOI-1452, which was confirmed through subsequent observations by a Japanese team.
Science paper:
The Astronomical Journal
See the full article here.
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The Université de Montréal is a French-language public research university in Montreal, Quebec, Canada. The university’s main campus is located on the northern slope of Mount Royal in the neighbourhoods of Outremont and Côte-des-Neiges. The institution comprises thirteen faculties, more than sixty departments and two affiliated schools: the Polytechnique Montréal (School of Engineering; formerly the École Polytechnique de Montréal) and HEC Montréal (School of Business). It offers more than 650 undergraduate programmes and graduate programmes, including 71 doctoral programmes.
The university was founded as a satellite campus of the Université Laval in 1878. It became an independent institution after it was issued a papal charter in 1919 and a provincial charter in 1920. Université de Montréal moved from Montreal’s Quartier Latin to its present location at Mount Royal in 1942. It was made a secular institution with the passing of another provincial charter in 1967.
The school is co-educational, and has 34,335 undergraduate and 11,925 post-graduate students (excluding affiliated schools). Alumni and former students reside across Canada and around the world, with notable alumni serving as government officials, academics, and business leaders.
Research
Université de Montréal is a member of the U15, a group that represents 15 Canadian research universities. The university includes 465 research units and departments. In 2018, Research Infosource ranked the university third in their list of top 50 research universities; with a sponsored research income (external sources of funding) of $536.238 million in 2017. In the same year, the university’s faculty averaged a sponsored research income of $271,000, while its graduates averaged a sponsored research income of $33,900.
Université de Montréal research performance has been noted in several bibliometric university rankings, which uses citation analysis to evaluate the impact a university has on academic publications. In 2019, The Performance Ranking of Scientific Papers for World Universities ranked the university 104th in the world, and fifth in Canada. The University Ranking by Academic Performance 2018–19 rankings placed the university 99th in the world, and fifth in Canada.
Since 2017, Université de Montréal has partnered with the McGill University (CA) on Mila (research institute), a community of professors, students, industrial partners and startups working in AI, with over 500 researchers making the institute the world’s largest academic research center in deep learning. The institute was originally founded in 1993 by Professor Yoshua Bengio.
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