Ground-based follow-up observations of TRAPPIST-1 transits in the near-infrared

Abstract

The TRAPPIST-1 planetary system is a favorable target for the atmospheric characterization of temperate earth-sized exoplanets by means of transmission spectroscopy with the forthcoming James Webb Space Telescope (JWST). A possible obstacle to this technique could come from the photospheric heterogeneity of the host star that could affect planetary signatures in the transit transmission spectra. To constrain further this possibility, we gathered an extensive photometric data set of 25 TRAPPIST-1 transits observed in the near-IR J band (1.2 $\mu$m) with the UKIRT and the AAT, and in the NB2090 band (2.1 $\mu$m) with the VLT during the period 2015-2018. In our analysis of these data, we used a special strategy aiming to ensure uniformity in our measurements and robustness in our conclusions. We reach a photometric precision of $\sim 0.003$ (RMS of the residuals), and we detect no significant temporal variations of transit depths of TRAPPIST-1 b, c, e, and g over the period of three years. The few transit depths measured for planets d and f hint towards some level of variability, but more measurements will be required for confirmation. Our depth measurements for planets b and c disagree with the stellar contamination spectra originating from the possible existence of bright spots of temperature 4500 K. We report updated transmission spectra for the six inner planets of the system which are globally flat for planets b and g and some structures are seen for planets c, d, e, and f.

arXiv commentaccepted for publication in MNRAS

References in corpus (31)

• Analytic Lightcurves for Planetary Transit Searches
• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• Temperate Earth-sized planets transiting a nearby ultracool dwarf star
• New Neighbors from 2MASS: Activity and Kinematics at the Bottom of the Main Sequence
• The Transit Light Source Effect: False Spectral Features and Incorrect Densities for M-dwarf Transiting Planets
• A seven-planet resonant chain in TRAPPIST-1
• The nature of the TRAPPIST-1 exoplanets
• The Transit Light Curve Project. IX. Evidence for a Smaller Radius of the Exoplanet XO-3b
• Observing the Atmospheres of Known Temperate Earth-sized Planets with JWST
• Atmospheric reconnaissance of the habitable-zone Earth-sized planets orbiting TRAPPIST-1
• A combined transmission spectrum of the Earth-sized exoplanets TRAPPIST-1 b and c
• The TRAPPIST survey of southern transiting planets. I. Thirty eclipses of the ultra-short period planet WASP-43 b
• Habitable worlds with JWST: transit spectroscopy of the TRAPPIST-1 system?
• Feasibility Studies for the Detection of $O_2$ in an Earth-like Exoplanet
• Evolved Climates and Observational Discriminants for the TRAPPIST-1 Planetary System
• On Correlated-noise Analyses Applied To Exoplanet Light Curves
• The Near-Infrared Transmission Spectra of TRAPPIST-1 Planets b, c, d, e, f, and g and Stellar Contamination in Multi-Epoch Transit Spectra
• Early 2017 observations of TRAPPIST-1 with $\text{Spitzer}$
• Disentangling the planet from the star in late type M dwarfs: A case study of TRAPPIST-1g
• Stellar parameters for TRAPPIST-1
• A photometric study of the hot exoplanet WASP-19b
• Near-infrared Thermal Emission Detections of a number of hot Jupiters and the Systematics of Ground-based Near-infrared Photometry
• Limits on Clouds and Hazes for the TRAPPIST-1 Planets
• Possible Bright Starspots on TRAPPIST-1
• Search for a habitable terrestrial planet transiting the nearby red dwarf GJ 1214
• The 0.8-4.5$\mu$m broadband transmission spectra of TRAPPIST-1 planets
• Non-detection of Contamination by Stellar Activity in the Spitzer Transit Light Curves of TRAPPIST-1
• Understanding Stellar Contamination in Exoplanet Transmission Spectra as an Essential Step in Small Planet Characterization
• Simulating the galaxy cluster "El Gordo": gas motion, kinetic Sunyaev-Zel'dovich signal, and X-ray line features
• Time-resolved image polarimetry of Trappist-1 during planetary transits
• Thermal emission of WASP-48b in the Ks-band

Cited by in corpus (13)

• Aerosols in Exoplanet Atmospheres
• A review of possible planetary atmospheres in the TRAPPIST-1 system
• TRAPPIST-1: Global Results of the Spitzer Exploration Science Program {\it Red Worlds}
• Detectability of Molecular Signatures on TRAPPIST-1e through Transmission Spectroscopy Simulated for Future Space-Based Observatories
• Distinguishing between wet and dry atmospheres of TRAPPIST-1 e and f
• The dynamics of the TRAPPIST-1 system in the context of its formation
• Do the TRAPPIST-1 Planets Have Hydrogen-rich Atmospheres?
• Near-infrared transmission spectrum of TRAPPIST-1 h using Hubble WFC3 G141 observations
• GJ357: A low-mass planetary system uncovered by precision radial-velocities and dynamical simulations
• The TRAPPIST-1 JWST Community Initiative
• Gliese 12 b: A temperate Earth-sized planet at 12 pc ideal for atmospheric transmission spectroscopy
• Searching for a cometary belt around Trappist-1 with ALMA
• L 98-59: a Benchmark System of Small Planets for Future Atmospheric Characterization