ARES IV: Probing the atmospheres of the two warm small planets HD 106315 c and HD 3167 c with the HST/WFC3 camera

Abstract

We present an atmospheric characterization study of two medium sized planets bracketing the radius of Neptune: HD 106315 c (R${}_{\mathrm{P}}$=4.98 $\pm$ 0.23 R${}_{\oplus }$) and HD 3167 c (R${}_{\mathrm{P}}$=2.740${}_{-0.100}^{+0.106}$ R${}_{\oplus }$). We analyse spatially scanned spectroscopic observations obtained with the G141 grism (1.125 - 1.650 $\mu$m) of the Wide Field Camera 3 (WFC3) onboard the Hubble Space Telescope. We use the publicly available Iraclis pipeline and TauREx3 atmospheric retrieval code and we detect water vapor in the atmosphere of both planets with an abundance of ${\log }_{10}[{\mathrm{H}}_2\mathrm{O}]=-2.1_{-1.3}^{+0.7}$ ($\sim$5.68$\sigma$) and ${\log }_{10}[{\mathrm{H}}_2\mathrm{O}]=-4.1_{-0.9}^{+0.9}$ ($\sim$3.17$\sigma$) for HD 106315 c and HD 3167 c, respectively. The transmission spectrum of HD 106315 c shows also a possible evidence of ammonia absorption (${\log }_{10}[\mathrm{N}{\mathrm{H}}_3]=-4.3_{-2.0}^{+0.7}$, $\sim$1.97$\sigma$ -even if it is not significant-), whilst carbon dioxide absorption features may be present in the atmosphere of HD 3167 c in the $\sim$1.1-1.6~$\mu$m wavelength range (${\log }_{10}[\mathrm{C}{\mathrm{O}}_2]=-2.4_{-1.0}^{+0.7}$, $\sim$3.28$\sigma$). However the CO${}_2$ detection appears significant, it must be considered carefully and put into perspective. Indeed, CO${}_2$ presence is not explained by 1D equilibrium chemistry models, and it could be due to possible systematics. The additional contribution of clouds, CO and CH${}_4$ are discussed. HD 106315 c and HD 3167 c will be interesting targets for upcoming telescopes such as the James Webb Space Telescope (JWST) and the Atmospheric Remote-Sensing Infrared Exoplanet Large-Survey (Ariel).

Accepted for publication in AJ

References in corpus (34)

• Most 1.6 Earth-Radius Planets are not Rocky
• Growth Model Interpretation of Planet Size Distribution
• Accurate, Empirical Radii and Masses of Planets and their Host Stars with Gaia Parallaxes
• A Precise Water Abundance Measurement for the Hot Jupiter WASP-43b
• Water Vapor and Clouds on the Habitable-Zone Sub-Neptune Exoplanet K2-18b
• Tau-REx I: A next generation retrieval code for exoplanetary atmospheres
• Water Vapour Absorption in the Clear Atmosphere of an exo-Neptune
• Water vapour in the atmosphere of the habitable-zone eight Earth-mass planet K2-18 b
• A Sub-Neptune Exoplanet with a Low-Metallicity Methane-Depleted Atmosphere and Mie-Scattering Clouds
• Hubble Space Telescope Near-IR Transmission Spectroscopy of the Super-Earth HD 97658b
• PASTIS: Bayesian extrasolar planet validation. I. General framework, models, and performance
• Hubble PanCET: An extended upper atmosphere of neutral hydrogen around the warm Neptune GJ 3470 b
• Trends in Atmospheric Properties of Neptune-Size Exoplanets
• Irradiated ocean planets bridge super-Earth and sub-Neptune populations
• Effects of a fully 3D atmospheric structure on exoplanet transmission spectra: retrieval biases due to day-night temperature gradients
• Why is it so Cold in Here?: Explaining the Cold Temperatures Retrieved from Transmission Spectra of Exoplanet Atmospheres
• Exploring Biases of Atmospheric Retrievals in Simulated JWST Transmission Spectra of Hot Jupiters
• The Featureless Transmission Spectra of Two Super-Puff Planets
• Three's Company: An additional non-transiting super-Earth in the bright HD 3167 system, and masses for all three planets
• Strong biases in retrieved atmospheric composition caused by strong day-night chemical heterogeneities
• The Transiting System GJ1214: High-Precision Defocused Transit Observations and a Search for Evidence of Transit Timing Variation
• Exoplanet Spectroscopy and Photometry with the Twinkle Space Telescope
• The transiting multi-planet system HD3167: a 5.7 MEarth Super-Earth and a 8.3 MEarth mini-Neptune
• ARES I: WASP-76 b, A Tale of Two HST Spectra
• ARES II: Characterising the Hot Jupiters WASP-127 b, WASP-79 b and WASP-62 b with HST
• Two Small Planets Transiting HD 3167
• A new chemical scheme for giant planet thermochemistry. Update of the methanol chemistry and new reduced chemical scheme
• The Metal-Rich Atmosphere of the Neptune HAT-P-26b
• ArielRad: the Ariel Radiometric Model
• A Hubble PanCET Study of HAT-P-11b: A Cloudy Neptune with a Low Atmospheric Metallicity
• ARES III: Unveiling the Two Faces of KELT-7 b with HST WFC3
• Precise masses for the transiting planetary system HD 106315 with HARPS
• Ground-based photometry of the 21-day Neptune HD106315c
• Toward More Reliable Analytic Thermochemical-equilibrium Abundances

Cited by in corpus (27)

• Tracing the formation history of giant planets in protoplanetary disks with Carbon, Oxygen, Nitrogen and Sulphur
• Five key exoplanet questions answered via the analysis of 25 hot Jupiter atmospheres in eclipse
• ExoClock Project III: 450 new exoplanet ephemerides from ground and space observations
• DREAM I. Orbital architecture orrery
• The Rossiter-McLaughlin effect Revolutions: An ultra-short period planet and a warm mini-Neptune on perpendicular orbits
• ARES V: No Evidence For Molecular Absorption in the HST WFC3 Spectrum of GJ 1132 b
• A comparison of chemical models of exoplanet atmospheres enabled by TauREx 3.1
• The Ariel Target List: The Impact of TESS and the Potential for Characterising Multiple Planets Within a System
• Detecting the proposed CH4-CO2 biosignature pair with the James Webb Space Telescope: TRAPPIST-1e and the effect of cloud/haze
• Toward a multidimensional analysis of transmission spectroscopy. Part I: Computation of transmission spectra using a 1D, 2D, or 3D atmosphere structure
• A Temperature Trend for Clouds and Hazes in Exoplanets Atmospheres
• On spectroscopic phase-curve retrievals: H2 dissociation and thermal inversion in the atmosphere of the ultra-hot Jupiter WASP-103 b
• Importance of Sample Selection in Exoplanet Atmosphere Population Studies
• The transmission spectrum of WASP-17 b from the optical to the near-infrared wavelengths: combining STIS, WFC3 and IRAC datasets
• Alfnoor: assessing the information content of Ariel's low resolution spectra with planetary population studies
• A CHEOPS-enhanced view of the HD3167 system
• ARES VI: Viability of one-dimensional retrieval models for transmission spectroscopy characterization of exo-atmospheres in the era of JWST and Ariel
• Detecting molecules in Ariel low resolution transmission spectra
• Comparing transit spectroscopy pipelines at the catalogue level: evidence for systematic differences
• Tighter constraints on the atmosphere of GJ 436 b from combined high-resolution CARMENES and CRIRES${}^{+}$ observations
• Exploring the atmosphere of GJ 1132 b with CRIRES+
• The SPACE Program. I. The featureless spectrum of HD 86226 c challenges sub-Neptune atmosphere trends
• A re-analysis of equilibrium chemistry in five hot Jupiters
• Evidence for an Atmosphere on the Ultra-Short Period super-Earth HD 3167 b
• RAPOC : the Rosseland and Planck opacity converter. A user-friendly and fast opacity program for Python
• Disentangling Atmospheric Compositions of K2-18 b with Next Generation Facilities
• Grain Growth in Escaping Atmospheres: Implications for the Radius Inflation of Super-Puffs