TRAPPIST-1h as an Exo-Titan. I. The Role of Assumptions about Atmospheric Parameters in Understanding an Exoplanet Atmosphere
arXiv:2207.12358 · doi:10.3847/1538-4357/ac59bb
Abstract
The TRAPPIST-1 system is home to at least seven terrestrial planets and is a target of interest for future James Webb Space Telescope (JWST) observations. Additionally, these planets will be of interest to future missions making observations in the ultraviolet (UV). Although several of these planets are located in the traditional habitable zone, where liquid water could exist on the surface, TRAPPIST-1h is interesting to explore as a potentially habitable ocean world analog. In this study, we evaluate the observability of a Titan-like atmosphere on TRAPPIST-1h. The ability of the JWST or a future UV mission to detect specific species in the atmosphere at TRAPPIST-1h will depend on how far each species extends from the surface. In order to understand the conditions required for detection, we evaluate the input parameters used in one-dimensional models to simulate the structure of Titan-like atmospheres. These parameters include surface temperature and pressure, temperature profile as a function of distance from the surface, composition of the minor species relative to N 2, and the eddy diffusion coefficient. We find that JWST simulated spectra for cloud- and haze-free atmospheres are most sensitive to surface temperature, temperature gradients with altitude, and surface pressure. The importance of temperature gradients in JWST observations shows that a simple isothermal scale height is not ideal for determining temperature or atmospheric mean molecular mass in transit spectra from exoplanet atmospheres. We demonstrate that UV transmission spectra are sensitive to the upper atmosphere, where the exobase can be used to approximate the vertical extent of the atmosphere.
References in corpus (19)
- Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
- The Pale Orange Dot: The Spectrum and Habitability of Hazy Archean Earth
- Observing the Atmospheres of Known Temperate Earth-sized Planets with JWST
- The Detectability and Characterization of the TRAPPIST-1 Exoplanet Atmospheres with JWST
- Geophysical tests for habitability in ice-covered ocean worlds
- Disequilibrium biosignatures over Earth history and implications for detecting exoplanet life
- Photolytically generated aerosols in the mesosphere and thermosphere of Titan
- Titan solar occultation observations reveal transit spectra of a hazy world
- Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets Around Low-Mass Stars: the TRAPPIST-1 System
- A review of possible planetary atmospheres in the TRAPPIST-1 system
- A new astrobiological model of the atmosphere of Titan
- Haze Evolution in Temperate Exoplanet Atmospheres Through Surface Energy Measurements
- Into the UV: A precise transmission spectrum of HAT-P-41b using Hubble's WFC3/UVIS G280 grism
- Tidal Heating and the Habitability of the TRAPPIST-1 Exoplanets
- Distinguishing between wet and dry atmospheres of TRAPPIST-1 e and f
- UV Exoplanet Transmission Spectral Features as Probes of Metals and Rainout
- Do the TRAPPIST-1 Planets Have Hydrogen-rich Atmospheres?
- A mirage of the cosmic shoreline: Venus-like clouds as a statistical false positive for exoplanet atmospheric erosion
- Global Analysis of the TRAPPIST Ultra-Cool Dwarf Transit Survey