Charles-Édouard Boukaré Archives - News@91��ɫ

International research led by 91��ɫ U prof sheds light on 'lava planets'

egamulin — Tue, 29 Jul 2025 12:00:40 +0000

Novel models of planetary interiors give scientists a framework to interpret current observations of distant exoplanets from space- and ground-based telescopes

Artistic illustration of the internal structure of a lava planet in a cold state, showing a day‑side magma ocean overlain by a mineral atmosphere.The arrows indicate the direction of heat transport within the planet’s interior and the thermal radiation emitted from its night side. Credit: Romain Jean-Jaques (Instagram: @romainjean.jacques)

TORONTO, July 29, 2025 – A new paper led by a 91��ɫ professor and in Nature Astronomy introduces a simple theoretical framework to describe the evolution of the coupled interior–atmosphere system of hot rocky exoplanets known as “lava planets.”

“Lava planets are in such extreme orbital configurations that our knowledge of rocky planets in the solar system does not directly apply, leaving scientists uncertain about what to expect when observing lava planets,” says first author Charles-Édouard Boukaré, Assistant Professor in 91��ɫ’s Department of Physics and Astronomy in the Faculty of Science.

“Our simulations propose a conceptual framework for interpreting their evolution and provide scenarios to probe their internal dynamics and chemical changes over time. These processes, though greatly amplified in lava planets, are fundamentally the same as those that shape rocky planets in our own solar system.”

First author Charles-Édouard Boukaré

Exotic worlds may unveil processes driving planetary evolution

Lava planets are Earth- to super-Earth–sized worlds orbiting extremely close to their host stars, completing an orbit in less than a single Earth day. Much like Earth’s Moon, they are expected to be tidally locked, always showing the same face to their star. Their dayside surfaces reach such extreme temperatures that silicate rocks melt – and even vaporize – creating conditions unlike anything in our solar system. These exotic worlds, easily observable due to their ultra short orbital period, provide unique insights into the fundamental processes that shape planetary evolution.

Probing planetary interiors through atmosphere and surface properties

The study combines expertise in geophysical fluid mechanics, exoplanetary atmospheres, and mineralogy to explore how the compositions of lava planets evolve through a process akin to distillation. When rocks melt or vaporize, elements such as magnesium, iron, silicon, oxygen, sodium, and potassium partition differently between vapor, liquid, and solid phases. The unique orbital configuration of lava planets maintains vapor–liquid and solid–liquid equilibria over billions of years, driving long-term chemical evolution.

The paper, “The role of interior dynamics and differentiation on the surface and atmosphere of lava planets,” was co-authored by Daphné Lemasquerier (University of St Andrews), Nicolas B. Cowan (McGill University), Lisa Dang (University of Waterloo), Henri Samuel, James Badro, Aurélien Falco and Sébastien Charnoz (Université Paris Cité).

Using unprecedented numerical simulations, the team predicts two end-member evolutionary states:

• Fully molten interior (likely young planets): The atmosphere mirrors the bulk planetary composition, and heat transport within the molten interior keeps the nightside surface hot and dynamic.

• Mostly solid interior (likely older planets): Only a shallow lava ocean remains on the dayside, and the atmosphere becomes depleted in elements such as sodium, potassium, and iron.

Testing hypotheses with the James Webb Space Telescope

Boukaré explains that this research on lava exoplanets began as a highly exploratory effort with few initial expectations. It builds on a novel modeling approach he developed to study molten rocky planets in collaboration with colleagues at the Institute de Physique du Globe de Paris, Université Paris Cité, published in Nature earlier this year.

What began as an exploratory study has since opened a promising new line of research. The predictions outlined in this work helped secure 100 hours of observation time on the James Webb Space Telescope (JWST) — the most advanced infrared observatory ever built, featuring a 6.5‑metre segmented mirror and ultra‑sensitive instruments capable of probing the earliest galaxies and the atmospheres of distant exoplanets with unprecedented precision. These upcoming JWST observations, led by co-author Prof. Dang, will directly test the theoretical framework proposed in this study.

“We really hope we can observe and distinguish old lava planets from young lava planets. If we can do this, it would mark an important step toward moving beyond the traditional snapshot view of exoplanets,” says Boukaré.

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91��ɫ is a modern, multi-campus, urban university located in Toronto, Ontario. Backed by a diverse group of students, faculty, staff, alumni and partners, we bring a uniquely global perspective to help solve societal challenges, drive positive change, and prepare our students for success. 91��ɫ's fully bilingual Glendon Campus is home to Southern Ontario's Centre of Excellence for French Language and Bilingual Postsecondary Education. 91��ɫ’s campuses in Costa Rica and India offer students exceptional transnational learning opportunities and innovative programs. Together, we can make things right for our communities, our planet, and our future.

Media Contact: Emina Gamulin, 91��ɫ Media Relations, 437-217-6362, egamulin@yorku.ca

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91��ɫ U led research sheds light on earliest days of Earth’s formation

egamulin — Wed, 26 Mar 2025 16:34:59 +0000

Faculty of Science prof used novel approach of applying fluid dynamics and chemistry to planetary sciences for modelling study published in Nature

Wednesday March 26, TORONTO – New research led by a 91��ɫ professor sheds light on the earliest days of the Earth’s formation and potentially calls into question some earlier assumptions in planetary science about the early years of rocky planets. Establishing a direct link between the Earth’s interior dynamics occurring within the first 100 million years of its history and its present-day structure, the work is one of the first in the field to combine fluid mechanics with chemistry to better understand the Earth's early evolution.

“This study is the first to demonstrate, using a physical model, that the first-order features of Earth’s lower mantle structure were established four billion years ago, very soon after the planet came into existence,” says lead author Faculty of Science Assistant Professor in the Department of Physics and Astronomy at 91��ɫ.

The mantle is the rocky envelopment that surrounds the iron core of rocky planets. The structure and dynamics of the Earth’s lower mantle play a major role throughout Earth’s history as it dictates, among others, the cooling of the Earth’s core where the Earth’s magnetic field is generated.

Boukaré – originally from France – worked with research colleagues from his former institution, Université Paris Cité's James Badro and Henri Samuel, on the paper, , which was published today in Nature.

Boukaré says that while seismology, geodynamics, and petrology have helped answer many questions about the present-day thermochemical structure of Earth’s interior, a key question remained: how old are these structures, and how did they form? Trying to answer this, he says, is much like looking at a person in the form of an adult versus a child and understanding how the energetic conditions will not be the same.

Artistic view of Earth’s interior during mantle solidification in the first hundreds of millions of years of Earth’s history. Gravitational segregation of dense, iron-rich magma (in orange) likely formed a basal magma ocean atop the core, that can explain the present-day structure of the lower mantle.

“If you take kids, sometimes they do crazy things because they have a lot of energy, like planets when they are young. When we get older, we don't do as many crazy things, because our activity or level of energy decreases. So, the dynamic is really different, but there are some things that we do when we are really young that might affect our entire life,” he says “It’s the same thing for planets. There are some aspects of the very early evolution of planets that we can actually see in their structure today.”

To better understand old planets, we must first learn how young planets behave.

Since simulations of the Earth’s mantle focus mostly on present-day solid-state conditions, Boukaré had to develop a novel model to explore the early days of Earth when the mantle was much hotter and substantially molten, work that he has been doing since his PhD.

Boukaré’s model is based on a multiphase flow approach that allows for capturing the dynamics of magma solidification at a planetary scale. Using his model, he studied how the early mantle transitioned from a molten to a solid state. Boukaré and his team were surprised to discover that most of the crystals formed at low pressure, which he says creates a very different chemical signature than what would be produced at depth in a high-pressure environment. This challenges the prevailing assumptions in planetary sciences in how rocky planets solidify.

“Until now, we assumed the geochemistry of the lower mantle was probably governed by high-pressure chemical reactions, and now it seems that we need to account also for their low-pressure counterparts.”

Boukare says this work could also help predict the behaviour of other planets down the line.

“If we know some kind of starting conditions, and we know the main processes of planetary evolution, we can predict how planets will evolve.”

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Media Contact:

Emina Gamulin, 91��ɫ Media Relations, 437-217-6362, egamulin@yorku.ca

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