René Doyon
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View article: Mapping Atmospheric Features of the Planetary-mass Brown Dwarf SIMP 0136 with JWST NIRISS
Mapping Atmospheric Features of the Planetary-mass Brown Dwarf SIMP 0136 with JWST NIRISS Open
In this paper, we analyze James Webb Space Telescope Near-Infrared Imager and Slitless Spectrograph time-series spectroscopy data to characterize the atmosphere of the planetary-mass brown dwarf SIMP J01365662+093347. Principal component a…
View article: The Interpolation Constraint in the RV Analysis of M Dwarfs Using Empirical Templates
The Interpolation Constraint in the RV Analysis of M Dwarfs Using Empirical Templates Open
Precise radial velocity (pRV) measurements of M dwarfs in the near-infrared rely on empirical templates due to the lack of accurate stellar spectral models in this regime. Templates are assumed to approximate the true spectrum when constru…
View article: Mapping the Cloud-Driven Atmospheric Dynamics & Chemistry of an Isolated Exoplanet Analog with Harmonic Signatures
Mapping the Cloud-Driven Atmospheric Dynamics & Chemistry of an Isolated Exoplanet Analog with Harmonic Signatures Open
Young planetary-mass objects and brown dwarfs near the L/T spectral transition exhibit enhanced spectrophotometric variability over field brown dwarfs. Patchy clouds, auroral processes, stratospheric hot spots, and complex carbon chemistry…
View article: NIRPS and TESS reveal a peculiar system around the M dwarf TOI-756: A transiting sub-Neptune and a cold eccentric giant
NIRPS and TESS reveal a peculiar system around the M dwarf TOI-756: A transiting sub-Neptune and a cold eccentric giant Open
Context . The Near InfraRed Planet Searcher (NIRPS) joined HARPS on the 3.6-m ESO telescope at La Silla Observatory in April 2023, dedicating part of its Guaranteed Time Observations (GTO) program to the radial velocity follow-up of TESS p…
View article: Possible Evidence for the Presence of Volatiles on the Warm Super-Earth TOI-270 b
Possible Evidence for the Presence of Volatiles on the Warm Super-Earth TOI-270 b Open
The search for atmospheres on rocky exoplanets is a crucial step in understanding the processes driving atmosphere formation, retention, and loss. Past studies have revealed the existence of planets interior to the radius valley with densi…
View article: Wide Separation Planets in Time (WISPIT): Discovery of a Gap H<i>α</i> Protoplanet WISPIT 2b with MagAO-X
Wide Separation Planets in Time (WISPIT): Discovery of a Gap H<i>α</i> Protoplanet WISPIT 2b with MagAO-X Open
Excellent ( 21 ± 0 41) likely clearing a dust-free gap between the two brightest dust rings in the transitional disk. Our signal-to-noise ratio of 12.5 detection gave an H α ASDI contrast of (6.5 ± 0.5) × 10 −4 and an H α line fl…
View article: Strict Limits on Potential Secondary Atmospheres on the Temperate Rocky Exo-Earth TRAPPIST-1 d
Strict Limits on Potential Secondary Atmospheres on the Temperate Rocky Exo-Earth TRAPPIST-1 d Open
The nearby TRAPPIST-1 system, with its seven small rocky planets orbiting a late-type M8 star, offers an unprecedented opportunity to search for secondary atmospheres on temperate terrestrial worlds. In particular, the 0.8 R ⊕ TRAPPIST-1 d…
View article: Detailed Architecture of the L 98-59 System and Confirmation of a Fifth Planet in the Habitable Zone
Detailed Architecture of the L 98-59 System and Confirmation of a Fifth Planet in the Habitable Zone Open
The L 98-59 system, identified by TESS in 2019, features three transiting exoplanets in compact orbits of 2.253, 3.691, and 7.451 days around an M3V star, with an outer 12.83 day nontransiting planet confirmed in 2021 using ESPRESSO. The p…
View article: A New Brown Dwarf Orbiting an M Star and an Investigation of the Eccentricity Distribution of Transiting Long-period Brown Dwarfs
A New Brown Dwarf Orbiting an M Star and an Investigation of the Eccentricity Distribution of Transiting Long-period Brown Dwarfs Open
The orbital eccentricities of brown dwarfs encode valuable information on their formation and evolution history, providing insights into whether they resemble giant planets or stellar binaries. Here, we report the discovery of TOI-5575 b, …
View article: Studying the variability of the He triplet to understand the detection limits of evaporating exoplanet atmospheres
Studying the variability of the He triplet to understand the detection limits of evaporating exoplanet atmospheres Open
With more than a dozen significant detections, the helium triplet has emerged as a key tracer of evaporating exoplanet atmospheres. This near-infrared feature can be observed from the ground and holds great promise, especially with upcomin…
View article: Hydride ion continuum hides absorption signatures in the NIRPS near-infrared transmission spectrum of the ultra-hot gas giant WASP-189b
Hydride ion continuum hides absorption signatures in the NIRPS near-infrared transmission spectrum of the ultra-hot gas giant WASP-189b Open
Context . Ultra-hot Jupiters showcase one-of-a-kind extreme atmospheric conditions, including the dissociation of molecules into atomic species, ionisation, and significant day-to-night temperature contrasts. The proximity to their host st…
View article: Diving into the planetary system of Proxima with NIRPS
Diving into the planetary system of Proxima with NIRPS Open
We obtained 420 high-resolution spectra of Proxima, over 159 nights, using the Near Infra Red Planet Searcher (NIRPS). We derived 149 nightly binned radial velocity measurements with a standard deviation of 1.69 ms −1 and a median uncertai…
View article: NIRPS detection of delayed atmospheric escape from the warm and misaligned Saturn-mass exoplanet WASP-69 b
NIRPS detection of delayed atmospheric escape from the warm and misaligned Saturn-mass exoplanet WASP-69 b Open
Context . Near-infrared high-resolution échelle spectrographs unlock access to fundamental properties of exoplanets, from their atmospheric escape and composition to their orbital architecture, which can all be studied simultaneously from …
View article: A reliable activity proxy in SPIRou spectra of M dwarfs using machine learning
A reliable activity proxy in SPIRou spectra of M dwarfs using machine learning Open
Context . Recent instruments have extended radial velocity observations from the optical domain to the near-infrared range (NIR). In particular, this has allowed M dwarfs to be studied more extensively, which is notable because they are kn…
View article: Escaping Helium and a Highly Muted Spectrum Suggest a Metal-enriched Atmosphere on Sub-Neptune GJ 3090 b from JWST Transit Spectroscopy
Escaping Helium and a Highly Muted Spectrum Suggest a Metal-enriched Atmosphere on Sub-Neptune GJ 3090 b from JWST Transit Spectroscopy Open
Sub-Neptunes, the most common planet type, remain poorly understood. Their atmospheres are expected to be diverse, but their compositions are challenging to determine, even with JWST. Here, we present the first JWST spectroscopic study of …
View article: Ground-breaking exoplanet science with the ANDES spectrograph at the ELT
Ground-breaking exoplanet science with the ANDES spectrograph at the ELT Open
In the past decade the study of exoplanet atmospheres at high-spectral resolution, via transmission/emission spectroscopy and cross-correlation techniques for atomic/molecular mapping, has become a powerful and consolidated methodology. Th…
View article: A Moderate Albedo from Reflecting Aerosols on the Dayside of WASP-80 b Revealed by JWST/NIRISS Eclipse Spectroscopy
A Moderate Albedo from Reflecting Aerosols on the Dayside of WASP-80 b Revealed by JWST/NIRISS Eclipse Spectroscopy Open
Secondary eclipse observations of exoplanets at near-infrared wavelengths enable the detection of thermal emission and reflected stellar light, providing insights into the thermal structure and aerosol composition of their atmospheres. The…
View article: The Gl 229 System Revisited with the Line-by-line Framework: Planetary Signals Now Appear as Stellar Activity Ghosts
The Gl 229 System Revisited with the Line-by-line Framework: Planetary Signals Now Appear as Stellar Activity Ghosts Open
Gl 229 is a well-known system hosting the first confirmed brown dwarf (BD), Gl 229 B, discovered in 1995. Subsequent radial velocity (RV) follow-up of the star unveiled, in 2014, an exoplanet on a 471 days orbit with a minimum mass of ∼32 …
View article: The James Webb Interferometer: Space-based Interferometric Detections of PDS 70 b and c at 4.8 <i>μ</i> m
The James Webb Interferometer: Space-based Interferometric Detections of PDS 70 b and c at 4.8 <i>μ</i> m Open
We observed the planet-hosting system PDS 70 with the James Webb Interferometer, JWST's aperture masking interferometric mode within NIRISS. Observing with the F480M filter centered at 4.8 μ m, we simultaneously fit geometrical models to t…
View article: Promise and Peril: Stellar Contamination and Strict Limits on the Atmosphere Composition of TRAPPIST-1 c from JWST NIRISS Transmission Spectra
Promise and Peril: Stellar Contamination and Strict Limits on the Atmosphere Composition of TRAPPIST-1 c from JWST NIRISS Transmission Spectra Open
Attempts to probe the atmospheres of rocky planets around M dwarfs present both promise and peril. While their favorable planet-to-star radius ratios enable searches for even thin secondary atmospheres, their high activity levels and high-…
View article: Chemical Fingerprints of M Dwarfs: High-resolution Spectroscopy on 31 M Dwarfs with SPIRou
Chemical Fingerprints of M Dwarfs: High-resolution Spectroscopy on 31 M Dwarfs with SPIRou Open
We extend the methodology introduced by F. Jahandar et al. to determine the effective temperature and chemical abundances of 31 slowly rotating solar neighborhood M dwarfs (M1–M5) using high-resolution spectra from CFHT/SPIRou. This group …
View article: Three Years of High-contrast Imaging of the PDS 70 b and c Exoplanets at Hα with MagAO-X: Evidence of Strong Protoplanet Hα Variability and Circumplanetary Dust
Three Years of High-contrast Imaging of the PDS 70 b and c Exoplanets at Hα with MagAO-X: Evidence of Strong Protoplanet Hα Variability and Circumplanetary Dust Open
We present 3 yr of high-contrast imaging of the PDS 70 b and c accreting protoplanets with the new extreme AO system MagAO-X as part of the MaxProtoPlanetS survey of H α protoplanets. In 2023 and 2024, our sharp (25–27 mas FWHM), well-AO-c…
View article: Measuring Sub-Kelvin Variations in Stellar Temperature with High-resolution Spectroscopy
Measuring Sub-Kelvin Variations in Stellar Temperature with High-resolution Spectroscopy Open
The detection of stellar variability often relies on the measurement of selected activity indicators, such as coronal emission lines and nonthermal emissions. On the flip side, the effective stellar temperature is normally seen as one of t…
View article: Chemical Fingerprints of M Dwarfs: High-Resolution Spectroscopy on 31 M Dwarfs with SPIRou
Chemical Fingerprints of M Dwarfs: High-Resolution Spectroscopy on 31 M Dwarfs with SPIRou Open
We extend the methodology introduced by Jahandar et al. (2024) to determine the effective temperature and chemical abundances of 31 slowly-rotating solar neighborhood M dwarfs (M1-M5) using high-resolution spectra from CFHT/SPIRou. This gr…
View article: SPIRou observations of the young planet-hosting star PDS 70
SPIRou observations of the young planet-hosting star PDS 70 Open
This paper presents near-infrared spectropolarimetric and velocimetric observations of the young planet-hosting T Tauri star PDS 70, collected with SPIRou at the 3.6-m Canada–France–Hawaii Telescope from 2020 to 2024. Clear Zeeman signatur…
View article: Updated Forecast for TRAPPIST-1 Times of Transit for All Seven Exoplanets Incorporating JWST Data
Updated Forecast for TRAPPIST-1 Times of Transit for All Seven Exoplanets Incorporating JWST Data Open
The TRAPPIST-1 system has been extensively observed with JWST in the near-infrared with the goal of detecting atmospheric transit transmission spectra of these temperate, Earth-sized exoplanets. A byproduct has been much more precise times…
View article: JWST/NIRISS Reveals the Water-rich “Steam World” Atmosphere of GJ 9827 d
JWST/NIRISS Reveals the Water-rich “Steam World” Atmosphere of GJ 9827 d Open
With sizable volatile envelopes but smaller radii than the solar system ice giants, sub-Neptunes have been revealed as one of the most common types of planet in the galaxy. While the spectroscopic characterization of larger sub-Neptunes (2…
View article: Promise and Peril: Stellar Contamination and Strict Limits on the Atmosphere Composition of TRAPPIST-1c from JWST NIRISS Transmission Spectra
Promise and Peril: Stellar Contamination and Strict Limits on the Atmosphere Composition of TRAPPIST-1c from JWST NIRISS Transmission Spectra Open
Attempts to probe the atmospheres of rocky planets around M dwarfs present both promise and peril. While their favorable planet-to-star radius ratios enable searches for even thin secondary atmospheres, their high activity levels and high-…
View article: The JWST/NIRISS Deep Spectroscopic Survey for Young Brown Dwarfs and Free-floating Planets
The JWST/NIRISS Deep Spectroscopic Survey for Young Brown Dwarfs and Free-floating Planets Open
The discovery and characterization of free-floating planetary-mass objects (FFPMOs) is fundamental to our understanding of star and planet formation. Here we report results from an extremely deep spectroscopic survey of the young star clus…
View article: Updated forecast for TRAPPIST-1 times of transit for all seven exoplanets incorporating JWST data
Updated forecast for TRAPPIST-1 times of transit for all seven exoplanets incorporating JWST data Open
The TRAPPIST-1 system has been extensively observed with JWST in the near-infrared with the goal of measuring atmospheric transit transmission spectra of these temperate, Earth-sized exoplanets. A byproduct of these observations has been m…