tidally locked Archives - Astrobiology

Surface temperature of the 22 exoplanets in an aquaplanet configuration. Obliquity and eccentricity are set to zero, and all are tidally locked with Earth-like atmospheric chemistry and pressure. Level lines correspond to the temperatures of 223.15, 273.15, and 323.15 K. White lines indicate the terminator, that is, the boundary between the illuminated and the dark sides of a planet. Black dots indicate the prevalence of sea ice (ice fraction larger than 0.5). -- [astro-ph.EP]

Habitable Zones

Assessing The Climate And Habitability Of Tidally Locked Rocky Exoplanets

by Keith CowingAugust 28, 2026August 28, 2026

[astro-ph.EP] Tidally locked exoplanets orbiting M dwarf stars are prime targets in the search for habitable worlds, yet their complex climate dynamics challenge conventional models of habitability.

WASP-39b transmission spectra and cloud scenarios. Spectra are observed with JWST (orange), HST (magenta), and VLT (green) in comparison to models with different Fe content: full IWF Graz cloud model (black line), Fe[s] replaced (dark gray), FeS[s] replaced (middle gray), and all Fe-binding materials replaced (light gray). The Fe-free mixed-material cloud compositions provide a good fit in the near-IR but not in the optical. — astro-ph.EP

Exoplanets, -moons, -comets, Gas Giants, Status Report

Exoplanet Climate Characterization With Transit Asymmetries

by Keith CowingApril 28, 2026April 28, 2026

Context. Space missions such as CHEOPS, JWST, and PLATO facilitate detailed characterization of exoplanets, particularly close-in gas giants and their wide range of global temperatures and climate regimes.

A schematic diagram of the hycean Lotka-Volterra model we implement in this work. The schematic shows how various parameters in our model are connected in a vertical, one-dimensional water column.

AI - Data - Apps - Cybernetics, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Proxima Centauri, Status Report, TRAPPIST-1, Water/Hycean Worlds & Oceanography

Ecological Modelling Of Hycean Worlds

by Keith CowingMarch 25, 2026

New observations are opening the possibility of characterising habitable environments in exoplanetary systems, with the recent example of the candidate hycean world K2-18 b.

Temperature distributions and thermal phase curves of the TRAPPIST-1 e system. Panel (a): Snapshot of the effective emission temperature of TRAPPIST-1 e.

Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, TRAPPIST-1

The Influence Of Hypothetical Exomoons On Planetary Thermal Phase Curves

by Keith CowingMarch 22, 2026March 22, 2026

More than 200 moons exist in our Solar System, yet no exomoon has been confirmed to date. While the innermost two planets of the Solar System lack natural satellites and […]

Atmospheric conditions in the case with Sp = 0.4 S0, pN2 = 1.0 bar, pCO2 = 0.1 bar. Each case shows (a) horizontal distribution of surface temperature, (b) horizontal distribution of CO2 ice amount (c) horizontal distribution of H2O ice amount, and (d) mass streamfunction between the substellar point (SS) and antistellar point (AS) in tidally-locekd coordinate. In (a), (b), and (c), 0°of latitude and of longitude corresponds to the substellar point (SS). Note that horizontal axis in (d) represents the latitude in tidally-locked coordinate and the mass flux where the value is positive is anticlockwise circulation. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Status Report

Atmospheric Collapse And Habitability On Tidally-Locked Exoplanets

by Keith CowingMarch 12, 2026March 12, 2026

The habitability of terrestrial exoplanets orbiting M dwarfs is a key topic in the search for extraterrestrial life.

Select temporally averaged meridional mass streamfunctions taken from both tidally-locked (top row and bottom right) and exo-Earth-analogue (bottom left) atmospheric models. Panels in the left column show the (global) zonal mean of the circulation, whilst panels in the right column show the circulation calculated over a narrow (15◦ degree) zonal mean at the sub-stellar and anti-stellar points of our tidally-locked atmosphere respectively. Note that the meridional circulation is plotted on a log-scale with clockwise circulations shown in red and anti-clockwise circulations shown in blue. Together these circulations can combine to drive a net flow. -- astro-ph.EP

Analog Studies, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Status Report

The Response of Planetary Atmospheres to the Impact of Icy Comets III: Impact Driven Atmospheric Escape

by Keith CowingDecember 17, 2025December 17, 2025

In an Earth-analogue atmosphere, water vapour is a key carrier of hydrogen in the lower atmosphere with its transport above the tropopause controlling the atmospheric hydrogen escape rate.

Deep Space Climate Observatory (DSCOVR) satellite's EPIC maintains a constant view of the fully illuminated Earth as it rotates, providing scientific observations of ozone, vegetation, cloud height and aerosols in the atmosphere. About twice a year the camera captures the Moon and Earth together as the orbit of DSCOVR crosses the orbital plane of the Moon. These images were taken between 3:50 p.m. and 8:45 p.m. EDT showing the moon moving over the Pacific Ocean near North America. The North Pole is in the upper left corner of the image. It is in the original orientation as taken by the spacecraft. larger image

Exoplanets, -moons, -comets, Moon, Press Release

Initial Conditions For Tidal Synchronisation Of A Planet By Its Moon

by Keith CowingSeptember 16, 2025September 16, 2025

Moons tidally interact with their host planets and stars. A close moon is quickly synchronised by the planet, or becomes captured in a higher spin-orbit resonance.

The radial gas temperature maps of planets from the 3D AFGKM ExoRad with a global temperature, Tglobal of 800K (left), 1600K (center) and 2400K (right) that orbit different host stars (top to bottom: A, G, M). The (Tgas, pgas)-maps gas are shown as equatorial slice plots. -- astro-ph.EP

AI - Data - Apps - Cybernetics, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Gas Giants, Status Report

Accelerating Exoplanet Climate Modelling: A Machine Learning Approach To Complement 3D GCM Grid Simulations

by Keith CowingAugust 15, 2025August 15, 2025

With the development of ever-improving telescopes capable of observing exoplanet atmospheres in greater detail and number, there is a growing demand for enhanced 3D climate models to support and help […]

This schematic depicts the set-up of the volatile exchange during initialization (t=0) and run time. For initialization, a surface temperature of 4000 K and a completely molten magma ocean is assumed, where the dissolved volatiles are in balance with the outgassed volatile content, set by the volatile melt fraction Fi . As the magma ocean solidifies, part of the volatile budget is deposited in the solid mantle. Further, atmospheric escape can remove H2O. These two sink terms thus reduce the amount of a volatile available in the fully coupled magma ocean-atmosphere system Mmoa i . The full overview of all included processes, including radiogenic heating, is shown in Barth et al. (2021, Fig. 1) -- astro-ph.EP

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Lava / magma ocean / Volcanic Worlds, Press Release, TRAPPIST-1

From CO2- to H2O-dominated Atmospheres And Back — How Mixed Outgassing Changes The Volatile Distribution In Magma Oceans Around M Dwarf Stars [TRAPPIST-1]

by Keith CowingMay 24, 2025May 24, 2025

We investigate the impact of CO2 on TRAPPIST-1 e, f and g during the magma ocean stage. These potentially habitable rocky planets are currently the most accessible for astronomical observations.

The location of magnetic nulls and separators for right- a tidally locked planet, and left- a fast-rotating planet (10 hours rotation period). The scale and size of Earth’s magnetosphere are consistent across both panels in the figure. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Magnetic Fields, Electromagnetism, bioelectricity,, Space Weather & Heliophysics, Status Report

Impacts Of Tidal Locking On Magnetospheric Energy Input To Exoplanet Atmospheres

by Keith CowingMay 23, 2025May 23, 2025

We investigate the effect of planetary corotation on energy dissipation within the magnetosphere-ionosphere system of exoplanets.