Improved characterization of the TOI-2141 system: a dense sub-Neptune with non-transiting inner and outer companions

Abstract

We aim to refine the fundamental parameters of the TOI-2141 planetary system, which includes a transiting sub-Neptune orbiting a Sun-like star in a relatively long orbit of 18.26 days, by combining new photometric and spectroscopic observations. We analyze new space-based photometry from TESS and CHEOPS as well as 61 radial velocity measurements from HARPS-N. We perform individual and joint photometric and RV analyses using several modeling tools within a Bayesian model comparison framework. We refine the radius and mass of the transiting planet TOI-2141 b to 3.15 $\pm$ 0.04 $R_{\oplus }$ and 20.1 $\pm$ 1.6 $M_{\oplus }$, respectively, five and two times more precise than the previously reported values. Our radial velocity analysis reveals two additional non-transiting companions with orbital periods of 5.46 and 60.45 days. Despite the innermost planet's high geometric transit probability, we find no evidence for transits in the photometric data. The bulk properties of TOI-2141 b suggest a significant volatile envelope atop an Earth-like core, with modeling indicating a hydrogen-rich atmosphere that may have experienced mild photoevaporation over the system's history. Planets b and c must exhibit a modest mutual inclination of at least 2.4 degrees.

arXiv commentAccepted for publication in A&A

References in corpus (62)

• emcee: The MCMC Hammer
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• MESA Isochrones and Stellar Tracks (MIST). I: Solar-Scaled Models
• dynesty: A Dynamic Nested Sampling Package for Estimating Bayesian Posteriors and Evidences
• 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
• Bayes in the sky: Bayesian inference and model selection in cosmology
• The Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)
• batman: BAsic Transit Model cAlculatioN in Python
• A new generation of PARSEC-COLIBRI stellar isochrones including the TP-AGB phase
• Kepler Presearch Data Conditioning II - A Bayesian Approach to Systematic Error Correction
• Gaia Early Data Release 3: Parallax bias versus magnitude, colour, and position
• Efficient, uninformative sampling of limb darkening coefficients for two-parameter laws
• Kepler Presearch Data Conditioning I - Architecture and Algorithms for Error Correction in Kepler Light Curves
• Rotation Periods of 34,030 Kepler Main-Sequence Stars: The Full Autocorrelation Sample
• The TESS Input Catalog and Candidate Target List
• Understanding the Mass-Radius Relation for Sub-Neptunes: Radius as a Proxy for Composition
• Spectroscopic parameters for 451 stars in the HARPS GTO planet search program. Stellar [Fe/H] and the frequency of exo-Neptunes
• Growth Model Interpretation of Planet Size Distribution
• RadVel: The Radial Velocity Modeling Toolkit
• Spectrum radial velocity analyser (SERVAL). High-precision radial velocities and two alternative spectral indicators
• Mass-Radius Relation for Rocky Planets based on PREM
• The HARPS-TERRA project I. Description of the algorithms, performance and new measurements on a few remarkable stars observed by HARPS
• Juliet: a versatile modelling tool for transiting and non-transiting exoplanetary systems
• A Framework for Quantifying the Degeneracies of Exoplanet Interior Compositions
• A new code for automatic determination of equivalent widths: Automatic Routine for line Equivalent widths in stellar Spectra (ARES)
• High order symplectic integrators for perturbed Hamiltonian systems
• SWEET-Cat: A catalogue of parameters for Stars With ExoplanETs I. New atmospheric parameters and masses for 48 stars with planets
• The CHEOPS mission
• CHEOPS: A Transit Photometry Mission for ESA's Small Mission Programme
• CLES, Code Liegeois d'Evolution Stellaire
• Revisited Mass-Radius relations for exoplanets below 120 Earth masses
• Stellar Winds on the Main-Sequence II: the Evolution of Rotation and Winds
• ARES v2 - new features and improved performance
• A pair of planets around HD 202206 or a circumbinary planet?
• AQUA: A Collection of H${}_2$O Equations of State for Planetary Models
• The Evolution of Stellar Rotation and the hydrogen atmospheres of habitable-zone Terrestrial Planets
• The HARPS search for southern extra-solar planets XIX. Characterization and dynamics of the GJ876 planetary system
• SOPHIE+: First results of an octagonal-section fiber for high-precision radial velocity measurements
• On Correlated-noise Analyses Applied To Exoplanet Light Curves
• A grid of upper atmosphere models for 1--40 MEARTH planets: application to CoRoT-7 b and HD219134 b,c
• Expected performances of the Characterising Exoplanet Satellite (CHEOPS) III. Data reduction pipeline: architecture and simulated performances
• Age consistency between exoplanet hosts and field stars
• Planetary system around the nearby M dwarf GJ 357 including a transiting, hot, Earth-sized planet optimal for atmospheric characterization
• Overcoming the limitations of the energy-limited approximation for planet atmospheric escape
• Revising the ages of planet-hosting stars
• SWEET-Cat 2.0: The Cat just got SWEETer; Higher quality spectra and precise parallaxes from GAIA eDR3
• Stacked Bayesian general Lomb-Scargle periodogram: Identifying stellar activity signals
• CHEOPS observations of the HD 108236 planetary system: A fifth planet, improved ephemerides, and planetary radii
• Analysis of Early Science observations with the CHaracterising ExOPlanets Satellite (CHEOPS) using pycheops
• The GAPS Programme with HARPS-N at TNG. VII. Putting exoplanets in the stellar context: magnetic activity and asteroseismology of $\tau$ Bootis A
• Majority of water hides deep in the interiors of exoplanets
• From super-Earths to sub-Neptunes: Observational constraints and connections to theoretical models
• WASP-186 and WASP-187: two hot Jupiters discovered by SuperWASP and SOPHIE with additional observations by TESS
• How Deep Is the Ocean? Exploring the phase structure of water-rich sub-Neptunes
• Reinvestigating $\alpha$ Cen AB in light of asteroseismic forward and inverse methods
• Machine learning inference of the interior structure of low-mass exoplanets
• ExoMDN: Rapid characterization of exoplanet interior structures with Mixture Density Networks
• Statistical methods for exoplanet detection with radial velocities
• Discovery of a hot, transiting, Earth-sized planet and a second temperate, non-transiting planet around the M4 dwarf GJ 3473 (TOI-488)
• Gaussian processes for radial velocity modeling Better rotation periods and planetary parameters with the quasi-periodic kernel and constrained priors
• TOI-1736 and TOI-2141: two systems including sub-Neptunes around solar analogs revealed by TESS and SOPHIE