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Experts in: Origin and evolution of solid surface planets

Bastien, Pierre


Professeur associé

My research deals mostly with star and planetary system formation. This is one of the priority research areas identified by the Canadian astronomical community. For this research, I mainly use light polarization as a means of gathering data.

Here are two examples of my ongoing research projects:

  1. Natural light vibrates in a plane that varies continuously and at random. When it vibrates in a preferential plane, we say that it is polarized. For measuring polarization from celestial objects, I am supervising a new polarimeter being built for the Mont Mégantic Observatory, POMM, that will be 100 times more precise than the one currently in use. Light from a young star is scattered and polarized by microscopic dust grains. By measuring this polarization, we can learn more about the properties of the grains and the distribution of matter around young stars or with disks of debris. Combining these data with other observations and with modelling, we learn about conditions in protoplanetary disks where planets are formed. I will also be observing stars with exoplanets to learn about the properties of the atmospheres of these planets and determine the inclination of their orbits.
  2. I also built a polarimeter, POL-2, for the James-Clerk-Maxwell radiotelescope on Mauna Kea in Hawaii. It will soon give us information about magnetic fields in dense molecular clouds and star formation processes. We want to find out if magnetic fields are more important than turbulence (or vice versa) in slowing star formation processes, because observations show us that they are slower than what our models predict.

Areas of expertise

  • Star formation
  • Polarimetry
  • Young stars

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Benneke, Björn


Professeur adjoint

The next five years present a truly unique opportunity in the history of planetary astrophysics. For the first time, the observational techniques, the theoretical models, and a sufficient number of known exoplanets orbiting nearby stars are available to spectroscopically characterize a wide diversity of planets. Planets ranging from blazingly hot giant planets to temperate Earth-sized planets in the habitable zone of their host stars.

Many unanswered questions remain: How and where do planets form? What materials make up their interiors? What gases are in their atmospheres? What role do clouds and hazes play? How big can a terrestrial planet be? How small can a gaseous planet be? And finally, what planets are capable of hosting life?

Professor Benneke’s team is currently in an exceptional position to address many of the questions above because they are currently conducting several unprecedented large observational programs using the Hubble Space Telescope, the Spitzer Space Telescope, and the 10-meter Keck observatories. They have developed powerful analysis and modeling framework to interpret these unique data sets. The main areas that Professor Benneke’s group is working on are:

  • Exploring the diversity of planetary atmospheres on super-Earths and exo-Neptunes using Hubble Space Telescope transit spectroscopy. Professor Benneke is the principal investigator of the largest Hubble Space Program in the world to characterize small exoplanets.
  • Probing the formation of giant planets using high-resolution near-infrared spectroscopy from 10-meter Keck telescopes
  • Atmospheric characterization and mapping of exoplanets using the upcoming James Webb Space Telescope (JWST)
  • Understanding the exotic cloud types on exoplanets
  • Discovery and initial characterization of prime targets for future JWST characterization using K2, TESS, and ground-based follow-up

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