The enigmatic nature of 55 Cancri e has defied theoretical explanation. Any explanation needs to account for the observed variability of its secondary eclipse depth, which is at times consistent […]
Atmospheres, Climate, Weather
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, TRAPPIST-1, Water/Hycean Worlds & Oceanography
Heating And Ionization By Non-thermal Electrons In The Upper Atmospheres Of Water-rich Exoplanets
Context. The long-term evolution of an atmosphere and the remote detectability of its chemical constituents are susceptible to how the atmospheric gas responds to stellar irradiation. The response remains poorly […]
![Mass fraction of 4 different PAHs, H2O, CH4, HCN, CO, and C2H2 for transiting planet (Teff = 1300K, Tint = 200K, [Fe/H] = 1.0, and log(g) = 3.0) for different C/O ratios -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2023/08/polycyclic.png?resize=1200%2C718&ssl=1)
Posted inAstrochemistry, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
Polycyclic Aromatic Hydrocarbons in Exoplanet Atmospheres I. Thermochemical Equilibrium Models
Context: Polycyclic Aromatic Hydrocarbons, largely known as PAHs, are widespread in the universe and have been identified in a vast array of astronomical observations from the interstellar medium to protoplanetary […]
Posted inAtmospheres, Climate, Weather, Biophysics, Magnetic Fields, Electromagnetism, bioelectricity,, Press Release, Radiation
Geomagnetic Field Protects Earth From Electron Showers
Understanding the ionosphere high in the Earth’s atmosphere is important due to its effects on communications systems, satellites and crucial chemical features including the ozone layer. New insights into the […]
Posted inAstrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Lava / magma ocean / Volcanic Worlds, Status Report
Interior Dynamics Of Super-Earth 55 Cancri e
The ultra-short-period super-Earth 55 Cancri e has a measured radius of 1.8 Earth radii. Previous thermal phase curve observations suggest a strong temperature contrast between the dayside and nightside of […]
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report
Bayesian Analysis for Remote Biosignature Identification on exoEarths (BARBIE) I: Using Grid-Based Nested Sampling in Coronagraphy Observation Simulations for H2O
Detecting H2O in exoplanet atmospheres is the first step on the path to determining planet habitability. Coronagraphic design currently limits the observing strategy used to detect H2O, requiring the choice […]
![Planets capable of supporting high O2 concentrations and, hence, technological civilizations. This figure shows the likely composition of planetary atmospheres based on mass and equilibrium temperature. For planets whose temperature and mass would lead to primarily CO2/N2/H2O atmospheres, high oxygen levels require a biological origin, i.e. photosynthesis. For higher equilibrium temperatures, high O2 levels can occur via the runaway greenhouse effect and the photolysis of water vapor at high altitudes. (Figure adapted from [7].) -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2023/08/TheOxygen.png?resize=1200%2C717&ssl=1)
Posted inAtmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Habitable Zones, SETI & Technosignatures, Status Report
The Oxygen Bottleneck For Technospheres
On Earth, the development of technology required easy access to open air combustion, which is only possible when oxygen partial pressure, P(O2), is above 18\%.
Posted inAstrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Lava / magma ocean / Volcanic Worlds, Status Report, Water/Hycean Worlds & Oceanography
The Role of Magma Oceans in Maintaining Surface Water on Rocky Planets Orbiting M-Dwarfs
Earth-like planets orbiting M-dwarf stars, M-Earths, are currently the best targets to search for signatures of life. Life as we know it requires water. The habitability of M-Earths is jeopardized […]
Posted inAtmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Missions & Hardware, Status Report
Comparative Study of Planetary Atmospheres and Implications for Atmospheric Entry Missions
The study of planetary atmospheres is critical to our understanding of the origin and evolution of the Solar System. The combined effect of various physical and chemical processes over billions […]
![Phase curves of the normalised total and normalised linearly polarised flux of a cloudy planet with a wavy ocean surface and an Earth-like atmosphere in an edge-on orbit (adapted from Trees & Stam 2019). The wind speed over the ocean—which determines the wave height (Cox & Munk 1954)—is 7 m/s, and the clouds consist of spherical water droplets. The cloud coverage fraction is 0.5, and while the cloud pattern is patchy, the glint is always cloud-free. The fluxes are normalised such that the total (i.e., unpolarised + polarised) flux equals the planet’s geometric albedo at phase angle 𝛼 = 0 ◦ . In the bottom panel, we illustrate the scattering angle ranges of glories, rainbows, Rayleigh scattering, and ocean glint. Note that the features in the actual curves partly overlap. The glory illustration is taken from Zakovryashin & Prigarin (2020); all other illustrations are from unsplash.com [1, 2, 3]. This figure is best viewed in colour. -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2023/07/chasing-1.png?resize=1200%2C720&ssl=1)
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report
Chasing Rainbows And Ocean Glints: Inner Working Angle Constraints For The Habitable Worlds Observatory
NASA is engaged in planning for a Habitable Worlds Observatory (HabWorlds), a coronagraphic space mission to detect rocky planets in habitable zones and establish their habitability.