TOI-1759 b: a transiting sub-Neptune around a low mass star characterized with SPIRou and TESS

Abstract

We report the detection and characterization of the transiting sub-Neptune TOI-1759 b, using photometric time-series from TESS and near infrared spectropolarimetric data from SPIRou on the CFHT. TOI-1759 b orbits a moderately active M0V star with an orbital period of $18.849975\pm 0.000006$ d, and we measure a planetary radius and mass of $3.06\pm 0.22$ R${}_{\oplus }$ and $6.8\pm 2.0$ M${}_{\oplus }$. Radial velocities were extracted from the SPIRou spectra using both the CCF and the LBL methods, optimizing the velocity measurements in the near infrared domain. We analyzed the broadband SED of the star and the high-resolution SPIRou spectra to constrain the stellar parameters and thus improve the accuracy of the derived planet parameters. A LSD analysis of the SPIRou Stokes $V$ polarized spectra detects Zeeman signatures in TOI-1759. We model the rotational modulation of the magnetic stellar activity using a GP regression with a quasi-periodic covariance function, and find a rotation period of $35.65_{-0.15}^{+0.17}$ d. We reconstruct the large-scale surface magnetic field of the star using ZDI, which gives a predominantly poloidal field with a mean strength of $18\pm 4$ G. Finally, we perform a joint Bayesian MCMC analysis of the TESS photometry and SPIRou RVs to optimally constrain the system parameters. At $0.1176\pm 0.0013$ au from the star, the planet receives $6.4$ times the bolometric flux incident on Earth, and its equilibrium temperature is estimated at $433\pm 14$ K. TOI-1759 b is a likely gas-dominated sub-Neptune with an expected high rate of photoevaporation. Therefore, it is an interesting target to search for neutral hydrogen escape, which may provide important constraints on the planetary formation mechanisms responsible for the observed sub-Neptune radius desert.

Accepted for publication in the 10. Planets and planetary systems section of Astronomy & Astrophysics

References in corpus (31)

• The Transiting Exoplanet Survey Satellite
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
• Habitable Zones Around Main-Sequence Stars: Dependence on Planetary Mass
• Growth Model Interpretation of Planet Size Distribution
• Planets and Stellar Activity: Hide and Seek in the CoRoT-7 system
• Determining stellar atmospheric parameters and chemical abundances of FGK stars with iSpec
• Accurate, Empirical Radii and Masses of Planets and their Host Stars with Gaia Parallaxes
• Stellar magnetism: empirical trends with age and rotation
• Modern stellar spectroscopy caveats
• Water Vapour Absorption in the Clear Atmosphere of an exo-Neptune
• Parallax Systematics and Photocenter Motions of Benchmark Eclipsing Binaries in Gaia EDR3
• The large-scale axisymmetric magnetic topology of avery-low-mass fully-convective star
• Inferring probabilistic stellar rotation periods using Gaussian processes
• Stellar activity of planetary host star HD 189733
• Eclipsing Binary Stars as Benchmarks for Trigonometric Parallaxes in the Gaia Era
• Hubble PanCET: An extended upper atmosphere of neutral hydrogen around the warm Neptune GJ 3470 b
• Barycentric Corrections at 1 cm/s for precise Doppler velocities
• Empirical, Accurate Masses and Radii of Single Stars with TESS and Gaia
• SPIRou: nIR velocimetry & spectropolarimetry at the CFHT
• The evolution of surface magnetic fields in young solar-type stars II: The early main sequence (250-650 Myr)
• Precise time-series photometry for the Kepler-2.0 mission
• SPIRou Input Catalog: Activity, Rotation and Magnetic Field of Cool Dwarfs
• Current Population Statistics Do Not Favor Photoevaporation over Core-Powered Mass Loss as the Dominant Cause of the Exoplanet Radius Gap
• Spin-orbit alignment and magnetic activity in the young planetary system AU Mic
• Transmission spectroscopy for the warm sub-Neptune HD3167c: evidence for molecular absorption and a possible high metallicity atmosphere
• Multi-instrumental view of magnetic fields and activity of $\epsilon$ Eridani with SPIRou, NARVAL, and TESS
• The SPIRou wavelength calibration for precise radial velocities in the near infrared
• Estimating fundamental parameters of nearby M dwarfs from SPIRou spectra

Cited by in corpus (21)

• Line-by-line velocity measurements, an outlier-resistant method for precision velocimetry
• APERO: A PipelinE to Reduce Observations -- Demonstration with SPIRou
• TOI-1452 b: SPIRou and TESS reveal a super-Earth in a temperate orbit transiting an M4 dwarf
• The TESS-Keck Survey XX: 15 New TESS Planets and a Uniform RV Analysis of all Survey Targets
• Optical and near-infrared stellar activity characterization of the early M dwarf Gl~205 with SOPHIE and SPIRou
• TESS discovery of a sub-Neptune orbiting a mid-M dwarf TOI-2136
• The space weather around the exoplanet GJ 436b
• $\text{Wapiti}$: a data-driven approach to correct for systematics in RV data -- Application to SPIRou data of the planet-hosting M dwarf GJ 251
• A massive hot Jupiter orbiting a metal-rich early-M star discovered in the TESS full frame images
• TOI-1736 and TOI-2141: two systems including sub-Neptunes around solar analogs revealed by TESS and SOPHIE
• A sub-Neptune planet around TOI-1695 discovered and characterized with SPIRou and TESS
• The CARMENES search for exoplanets around M dwarfs. Line-by-line sensitivity to activity in M dwarfs
• Characterization of seven transiting systems including four warm Jupiters from SOPHIE and TESS
• A transiting giant planet in orbit around a 0.2-solar-mass host star
• Long period modulation of the classical T Tauri star CI Tau: evidence for an eccentric close-in massive planet at 0.17 au
• Characterizing planetary systems with SPIRou: a temperate sub-Neptune exoplanet orbiting the nearby fully-convective star GJ 1289 and a candidate around GJ 3378
• TOI-3568 b: a super-Neptune in the sub-Jovian desert
• The SPIRou Legacy Survey: near-infrared and optical radial velocity analysis of Gl 480 and Gl 382 using SPIRou, HARPS and CARMENES spectrographs
• Near-IR and optical radial velocities of the active M dwarf star Gl 388 (AD Leo) with SPIRou at CFHT and SOPHIE at OHP: A 2.23 day rotation period and no evidence for a corotating planet
• Scientific Validation of the SPARC4 Pipeline: Multi-band Imaging, Polarimetry, and Photometric Time Series for Improved Characterization of Transiting Exoplanets
• Magnetic geometry of M dwarfs in the southern PLATO field