Hubble WFC3 Spectroscopy of the Habitable-zone Super-Earth LHS 1140 b

Abstract

Atmospheric characterisation of temperate, rocky planets is the holy grail of exoplanet studies. These worlds are at the limits of our capabilities with current instrumentation in transmission spectroscopy and challenge our state-of-the-art statistical techniques. Here we present the transmission spectrum of the temperate Super-Earth LHS 1140b using the Hubble Space Telescope (HST). The Wide Field Camera 3 (WFC3) G141 grism data of this habitable zone (T${}_{\mathrm{eq}}$ = 235 K) Super-Earth (R = 1.7 $R_{\oplus }$), shows tentative evidence of water. However, the signal-to-noise ratio, and thus the significance of the detection, is low and stellar contamination models can cause modulation over the spectral band probed. We attempt to correct for contamination using these models and find that, while many still lead to evidence for water, some could provide reasonable fits to the data without the need for molecular absorption although most of these cause also features in the visible ground-based data which are nonphysical. Future observations with the James Webb Space Telescope (JWST) would be capable of confirming, or refuting, this atmospheric detection.

Accepted for publication in AJ on 30th October 2020

References in corpus (14)

• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• Growth Model Interpretation of Planet Size Distribution
• Toward a Deterministic Model of Planetary Formation V. Accumulation Near the Ice Line
• The Mass of Kepler-93b and The Composition of Terrestrial Planets
• Detectability of atmospheric features of Earth-like planets in the habitable zone around M dwarfs
• A reassessment of the in situ formation of close-in super-Earths
• Planetary system LHS 1140 revisited with ESPRESSO and TESS
• Exoplanet Spectroscopy and Photometry with the Twinkle Space Telescope
• ARES II: Characterising the Hot Jupiters WASP-127 b, WASP-79 b and WASP-62 b with HST
• Characterizing K2 Candidate Planetary Systems Orbiting Low-Mass Stars I: Classifying Low-mass Host Stars Observed During Campaigns 1-7
• ARES III: Unveiling the Two Faces of KELT-7 b with HST WFC3
• On the Diversity of M-Star Astrospheres and the Role of Galactic Cosmic Rays Within
• KELT-11 b: Abundances of water and constraints on carbon-bearing molecules from the Hubble transmission spectrum
• The high-energy radiation environment of the habitable-zone super-Earth LHS 1140b

Cited by in corpus (54)

• A JWST transmission spectrum of a nearby Earth-sized exoplanet
• 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
• 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
• LHS 1140 b is a potentially habitable water world
• Haze Evolution in Temperate Exoplanet Atmospheres Through Surface Energy Measurements
• The Ariel Target List: The Impact of TESS and the Potential for Characterising Multiple Planets Within a System
• Hints of a sulfur-rich atmosphere around the 1.6 R${}_{\oplus }$ Super-Earth L98-59 d from JWST NIRSpec G395H transmission spectroscopy
• Super-Earths and Earth-like Exoplanets
• The First Near-Infrared Transmission Spectrum of HIP 41378 f, a Low-Mass Temperate Jovian World in a Multi-Planet System
• Escaping Helium and a Highly Muted Spectrum Suggest a Metal-Enriched Atmosphere on Sub-Neptune GJ3090b from JWST Transit Spectroscopy
• Cleaning our Hazy Lens: Exploring Trends in Transmission Spectra of Warm Exoplanets
• Near-infrared transmission spectrum of TRAPPIST-1 h using Hubble WFC3 G141 observations
• Detecting the proposed CH4-CO2 biosignature pair with the James Webb Space Telescope: TRAPPIST-1e and the effect of cloud/haze
• TOI-1468: A system of two transiting planets, a super-Earth and a mini-Neptune, on opposite sides of the radius valley
• A transiting, temperate mini-Neptune orbiting the M dwarf TOI-1759 unveiled by TESS
• Detectability of biosignatures on LHS 1140 b
• Hubble WFC3 Spectroscopy of the Terrestrial Planets L~98-59~c \& d: No Evidence for a Clear Hydrogen Dominated Primary Atmosphere
• Confirmation of an He I evaporating atmosphere around the 650-Myr-old sub-Neptune HD235088 b (TOI-1430 b) with CARMENES
• Hubble WFC3 Spectroscopy of the Rocky Planet L 98-59 b: No Evidence for a Cloud-Free Primordial Atmosphere
• On spectroscopic phase-curve retrievals: H2 dissociation and thermal inversion in the atmosphere of the ultra-hot Jupiter WASP-103 b
• Cross-sections for heavy atmospheres: H${}_2$O continuum
• Sporadic Spin-Orbit Variations in Compact Multi-planet Systems and their Influence on Exoplanet Climate
• A Framework for Characterizing Transmission Spectra of Exoplanets with Circumplanetary Rings
• Planetary parameters, XUV environments and mass-loss rates for nearby gaseous planets with X-ray detected host-stars
• Microphysics of Water Clouds in the Atmospheres of Y Dwarfs and Temperate Giant Planets
• The transmission spectrum of WASP-17 b from the optical to the near-infrared wavelengths: combining STIS, WFC3 and IRAC datasets
• Detecting Biosignatures in the Atmospheres of Gas Dwarf Planets with the James Webb Space Telescope
• The Atmospheres of Rocky Exoplanets II. Influence of surface composition on the diversity of cloud condensates
• Liquid Water on Cold Exo-Earths via Basal Melting of Ice Sheets
• Characterization of starspots on a young M-dwarf K2-25: multi-band observations of stellar photometric variability and planetary transits
• Knobs and dials of retrieving JWST transmission spectra. I. The importance of p-T profile complexity
• Habitable Zone and Atmosphere Retention Distance (HaZARD) Stellar-evolution-dependent loss models of secondary atmospheres
• Cross-sections for heavy atmospheres: H${}_2$O self-broadening
• Impact of M-dwarf Stellar Wind and Photoevaporation on the Atmospheric Evolution of Small Planets
• Follow the Water: Finding Water, Snow and Clouds on Terrestrial Exoplanets with Photometry and Machine Learning
• Instrumentation prospects for rocky exoplanet atmospheres studies with high resolution spectroscopy
• A Population Analysis of 20 Exoplanets Observed from the Optical to the Near-infrared Wavelengths with HST: Evidence for Widespread Stellar Contamination
• TOI-4336 A b: A temperate sub-Neptune ripe for atmospheric characterization in a nearby triple M-dwarf system
• The Hubble PanCET program: The near-ultraviolet transmission spectrum of WASP-79b
• Potential Interior Structures and Habitability of Super-Earth Exoplanets LHS 1140 b, K2-18 b, TOI-1452 b and TOI-1468 c
• A reanalysis of the LHS 1140 b atmosphere observed with the Hubble Space Telescope
• Exploring the atmosphere of GJ 1132 b with CRIRES+
• Modeling the astrosphere of LHS~1140
• Helium escaping from the atmosphere of a nearby rocky exoplanet orbiting in a habitable zone
• A re-analysis of equilibrium chemistry in five hot Jupiters
• Exploring the habitability and interior composition of exoplanets lying within the extended habitable zone
• Knobs and dials of retrieving JWST transmission spectra. II. Impacts of pipeline-level differences on retrieval posteriors
• The DRAKE mission: finding the frequency of life in the Cosmos
• Disentangling Atmospheric Compositions of K2-18 b with Next Generation Facilities
• Effect of clouds on emission spectra for Super Venus
• L 98-59: a Benchmark System of Small Planets for Future Atmospheric Characterization
• PAStar: a model for stellar surface from the Sun to active stars