Radial velocity detection of the TRAPPIST-1 planetary system with SPIRou and NIRPS
20 affiliations
- 1Institut Trottier de recherche sur les exoplanètes, Département de Physique, Université de Montréal, 1375 Ave Thérèse-Lavoie-Roux
- 2CNRS, OMP, Université de Toulouse
- 3Department of Astronomy, University of Washington
- 4Université Grenoble Alpes, CNRS, IPAG
- 5LUPM, Université de Montpellier, CNRS
- 6Sterrewacht Leiden, Universiteit Leiden
- 7Canada-France-Hawai’i Telescope, CNRS
- 8Institut d’astrophysique de Paris, UMR7095 CNRS, Sorbonne Université
- 9Observatoire de Genève, Département d’Astronomie, Université de Genève
- 10Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Campus Universitário
- 11Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Rua das Estrelas
- 12Department of Earth, Planetary, and Space Sciences, University of California
- 13Department of Physics, McGill University
- 14Department of Physics & Astronomy, McMaster University
- 15Planétarium de Montréal, Espace pour la Vie, 4801 Ave Pierre-de Coubertin
- 16Instituto de Astrofísica de Canarias (IAC), Calle Vía Láctea s/n
- 17Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n
- 18Department of Astronomy & Astrophysics, University of Chicago
- 19Department of Physics, Engineering Physics, and Astronomy, Queen’s University
- 20Space Research and Planetary Sciences, Physikalisches Institut, Universität Bern
Abstract
The TRAPPIST-1 system is well known for its seven transiting Earth-sized exoplanets. It has been extensively studied and characterized, notably with transit timing variations (TTVs), to precisely measure the mass of the planets. Using near-infrared spectroscopic observations obtained as part of the SPIRou Legacy Survey and the NIRPS Guaranteed Time Observation programs, we aimed to verify those values through radial velocity (RV) measurements of the system. Our RV analysis reveals that the current data do not have the precision required to individually detect the TRAPPIST-1 planets. However, we confidently detect (Δ ln 𝒵 = 7.53, 1860:1 odds) the combined RV signature of the planets by using the relative masses derived from the TTV analysis, with TRAPPIST-1 b as a proxy for the whole system. For the first time, the RV signal of the TRAPPIST-1 system is recovered: we find a RV semi-amplitude of Kb = 3.65−0.83+0.78 m s−1. This corresponds to a planetary mass of Mp, b = 1.31 ± 0.29 M⊕ and demonstrates that the RV measurements are consistent with the TTV model (Mp, b; TTV = 1.374 ± 0.069 M⊕). Additionally, the NIRPS RVs constrain the presence of giant planets beyond the snow line, excluding Saturn-mass planets out to 2.7-yr orbits and Neptune-mass objects out to 20 d. Through RV, we determined the stellar activity period to be of 3.22−0.20+0.22 d. Its agreement with photometric measurements (K2 and TESS) confirms stellar rotation as the origin of the ~3.3-d periodicity observed for TRAPPIST-1. We further investigated stellar activity with SPIRou polarimetric measurements, and placed an upper limit on the longitudinal field (|Bl| < 40 G, 3σ). This limit is compatible with a weak multipolar large-scale magnetic geometry, as observed in some of the later-type rapidly rotating M dwarfs.
Related
- The GAPS programme at TNG. LXXIX. New mass constraints for the infant planets in the V1298,Tau system through a long-term radial-velocity monitoring with HARPS-N
- Exoplanet Detection Techniques: Radial Velocity
- Radial Velocity Evidence for a Post-mass-transfer Massive Binary System NaSt1
- The GAPS programme at TNG LXXIX. New mass constraints for the infant planets in the V1298 Tau system through a long-term radial velocity monitoring with HARPS-N
- VELOcities of CEpheids (VELOCE) III. Reconstructing radial velocity curves of classical Cepheids
BibTeX
@article{alexandrine2026radial,
title = {{Radial velocity detection of the TRAPPIST-1 planetary system with SPIRou and NIRPS}},
author = {L’Heureux Alexandrine and Doyon René and Cadieux Charles and Petit Pascal and Lim Olivia and Artigau Étienne and Cook Neil J. and Agol Eric and Bonfils Xavier and Morin Julien and Bellotti Stefano and Moutou Claire and Moranta Leslie and Donati Jean-François and Arnold Luc and Delfosse Xavier and Hébrard Guillaume and Allart Romain and Bouchy François and Mignon Lucile and de Castro Leão Izan and Mounzer Dany and Al Moulla Khaled and Baron Frédérique and Benneke Björn and Bouffard Mathis and Brinkman Casey and Canto Martins Bruno L. and Carmona Andrés and Cloutier Ryan and Cointepas Marion and Cowan Nicolas B. and Cristo Eduardo and de Lima Gomes Roseane and De Medeiros José Renan and Dumusque Xavier and Fontinele Dasaev O. and Forveille Thierry and Frensch Yolanda G. C. and Gagné Jonathan and González Hernández Jonay I. and Gromek Nicole and Hobson Melissa J. and Krishnamurthy Vigneshwaran and Lamontagne Pierrot and Malo Lison and Martioli Eder and Messias Yuri S. and Nielsen Louise D. and Osborn Ares and Parc Léna and Piaulet-Ghorayeb Caroline and Santos Nuno C. and Neil Skinner Bennett and Srivastava Avidaan and Stefanov Atanas K. and Suárez Mascareño Alejandro and Wade Gregg and Wardenier Joost P. and Weisserman Drew},
journal = {Astronomy \& Astrophysics},
year = {2026},
month = oct,
doi = {10.1051/0004-6361/202659920},
url = {https://doi.org/10.1051/0004-6361/202659920},
note = {CC BY},
}
RIS
TY - JOUR
TI - Radial velocity detection of the TRAPPIST-1 planetary system with SPIRou and NIRPS
AU - L’Heureux Alexandrine
AU - Doyon René
AU - Cadieux Charles
AU - Petit Pascal
AU - Lim Olivia
AU - Artigau Étienne
AU - Cook Neil J.
AU - Agol Eric
AU - Bonfils Xavier
AU - Morin Julien
AU - Bellotti Stefano
AU - Moutou Claire
AU - Moranta Leslie
AU - Donati Jean-François
AU - Arnold Luc
AU - Delfosse Xavier
AU - Hébrard Guillaume
AU - Allart Romain
AU - Bouchy François
AU - Mignon Lucile
AU - de Castro Leão Izan
AU - Mounzer Dany
AU - Al Moulla Khaled
AU - Baron Frédérique
AU - Benneke Björn
AU - Bouffard Mathis
AU - Brinkman Casey
AU - Canto Martins Bruno L.
AU - Carmona Andrés
AU - Cloutier Ryan
AU - Cointepas Marion
AU - Cowan Nicolas B.
AU - Cristo Eduardo
AU - de Lima Gomes Roseane
AU - De Medeiros José Renan
AU - Dumusque Xavier
AU - Fontinele Dasaev O.
AU - Forveille Thierry
AU - Frensch Yolanda G. C.
AU - Gagné Jonathan
AU - González Hernández Jonay I.
AU - Gromek Nicole
AU - Hobson Melissa J.
AU - Krishnamurthy Vigneshwaran
AU - Lamontagne Pierrot
AU - Malo Lison
AU - Martioli Eder
AU - Messias Yuri S.
AU - Nielsen Louise D.
AU - Osborn Ares
AU - Parc Léna
AU - Piaulet-Ghorayeb Caroline
AU - Santos Nuno C.
AU - Neil Skinner Bennett
AU - Srivastava Avidaan
AU - Stefanov Atanas K.
AU - Suárez Mascareño Alejandro
AU - Wade Gregg
AU - Wardenier Joost P.
AU - Weisserman Drew
PY - 2026
DA - 2026/10/24
JO - Astronomy & Astrophysics
DO - 10.1051/0004-6361/202659920
UR - https://doi.org/10.1051/0004-6361/202659920
AB - The TRAPPIST-1 system is well known for its seven transiting Earth-sized exoplanets. It has been extensively studied and characterized, notably with transit timing variations (TTVs), to precisely measure the mass of the planets. Using near-infrared spectroscopic observations obtained as part of the SPIRou Legacy Survey and the NIRPS Guaranteed Time Observation programs, we aimed to verify those values through radial velocity (RV) measurements of the system. Our RV analysis reveals that the current data do not have the precision required to individually detect the TRAPPIST-1 planets. However, we confidently detect (Δ ln 𝒵 = 7.53, 1860:1 odds) the combined RV signature of the planets by using the relative masses derived from the TTV analysis, with TRAPPIST-1 b as a proxy for the whole system. For the first time, the RV signal of the TRAPPIST-1 system is recovered: we find a RV semi-amplitude of Kb = 3.65−0.83+0.78 m s−1. This corresponds to a planetary mass of Mp, b = 1.31 ± 0.29 M⊕ and demonstrates that the RV measurements are consistent with the TTV model (Mp, b; TTV = 1.374 ± 0.069 M⊕). Additionally, the NIRPS RVs constrain the presence of giant planets beyond the snow line, excluding Saturn-mass planets out to 2.7-yr orbits and Neptune-mass objects out to 20 d. Through RV, we determined the stellar activity period to be of 3.22−0.20+0.22 d. Its agreement with photometric measurements (K2 and TESS) confirms stellar rotation as the origin of the ~3.3-d periodicity observed for TRAPPIST-1. We further investigated stellar activity with SPIRou polarimetric measurements, and placed an upper limit on the longitudinal field (|Bl| < 40 G, 3σ). This limit is compatible with a weak multipolar large-scale magnetic geometry, as observed in some of the later-type rapidly rotating M dwarfs.
SN - 0004-6361
SN - 1432-0746
ER -