My name is Ryan Cloutier and I am a fourth-year PhD candidate in the Department of Astronomy and Astrophysics at the University of Toronto. I am also a Centre for Planetary Sciences Graduate Fellow doing my thesis with Professors Kristen Menou and René Doyon at le Université de Montréal. As such, I am also affiliated with the Institute for Research on Exoplanets.
I am a member of the SPIRou and NIRPS science teams working on the radial velocity detection and characterization of exoplanets around M-dwarf stars. I employ statistical methods commonly used in machine learning to mitigate the effects of stellar jitter thus facilitating the detection of faint signals from small, Earth-like planets. My broad research interests include understanding the bulk properites of the sub-Neptune-sized exoplanet population which is informed by the continuing discovery of new exoplanets and by various observational opportunities afforded by certain exoplanets such as transmission sepctroscopy and direct imaging of small planets in the coming decades. In practise I work on developing robust techniques to both detect large numbers of new exoplanets as well as to characterize known exoplanets such as those found in transit around their host star and those which may be amenable to atmospheric characterization.
most of my research revolves around the endeavour of trying to detect Earth-like planets around nearby M-dwarf stars using the radial velocity method.
These stars are most effectively observed at near-infrared wavelengths where the majority of their flux is emitted and stellar absorption features, which are required to measure precise radial velocities, are abundant. To conduct observations of nearby M-dwarfs and search for faint planetary signals a number of innovative instruments are currently being designed and built including SPIRou and NIRPS; near-infrared spectrographs whose observations I will use to both detect new exoplanetary systems as well as to characterize the masses of known transiting planetary systems thus constraining their bulk densities; i.e. are they rocky Earth-like planets or gas giants more akin to Neptune.
Click here for my publications list on ADS.
Small planets around active stars
Thanks to the Kepler space mission we know that planets smaller than about the size of Neptune are extremely common around M-dwarfs. More precisely we know that these small planets are commonly found within their host star's habitable zone wherein the planet's surface temperature is temperate enough to theoretically sustain liquid water. M-dwarfs therefore represent exciting opportunities to find a large sample of small, potentially habitable planets. However M-dwarfs are also famously active exhibiting high levels of X-ray/UV radiation which can alter a planet's atmospheric composition as well as mask or even mimic planetary signals.
In my recent paper I describe the use of a trained mean Gaussian process regression model of the stellar jitter in radial velocity. Here we applied this technique to the GJ 1132 planetary system to model the stellar jitter and measure the detection completeness to additional planets hypothesized to exist within the system based on the high occurrence rate of planets around stars like GJ 1132.
This technique will prove to be useful when characterizing transiting planet candidates such as those that will be discovered with NASA's up-coming TESS mission. The mass characterization of these planets will be imperative to the interpretation of measurements of their atmosperes with the up-coming James Webb Space Telescope.
The following is a link to a PDF version of my full CV.