[Astrobiology via PubMed]. Photochemical organic hazes such as those found in the atmosphere of Titan, the largest satellite of Saturn, are mainly composed of reduced chemical components.
Photochemical haze
Posted inAtmospheres, Climate, Weather
Optical Constants of Photochemical Haze Analogs in N2-CH4-CO Atmospheres from 0.4 to 28.6 μm
[astro-ph.EP] Photochemical hazes play an important role in shaping the spectra and radiative balance of N2-dominated planetary atmospheres.
![Clouds may form via heterogeneous nucleation on top of ‘seed’ photochemical haze particles. Whether or not this pathway dominates over homogeneous nucleation—the process through which ‘pure’ clouds spontaneously form—depends on the microphysical contact angle between the relevant cloud and haze species. Smaller contact angles correspond to stronger cloud-haze interactions due to the increased affinity between the clouds and hazes. While this contact angle is unknown in the absence of lab data, heterogeneous nucleation is the primary cloud-formation pathway across the Solar System. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Wet-Removal.png?resize=1200%2C715&ssl=1)
Posted inAtmospheres, Climate, Weather
Wet Removal and Cloud Enhancement: The Microphysics of Cloud-Haze Interactions on Sub-Neptunes
[astro-ph.EP] Aerosols are a near-ubiquitous feature of sub-Neptune atmospheres, yet their microphysical nature remains poorly understood. Both condensate clouds and photochemical hazes have been proposed to explain observations, but have […]
![[LEFT] Haze mass mixing ratio, q1 [g g−1 ] (left column), and haze particle size , rh [nm] (right column), for the short formation timescale simulation at 10−5 bar (top row), 10−4 bar (second row), 10−3 bar (third row) and 10−2 bar (bottom row) pressure levels. The sub-stellar point is located at (0◦, 0◦). {RIGHT} same as LEFT but for the long haze formation timescale. -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/06/Three-dimensional.png?resize=1200%2C720&ssl=1)
Posted inAtmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
Three Dimensional Temporal Evolution Of Photochemical Haze In Exoplanet Atmospheres I. Description And Test Application To HD 189733b
The formation and global spatial distribution of photochemically produced haze particles remain a key process in exoplanet atmospheres for understanding their observed properties. We aim to develop a flexible haze […]
Posted inAtmospheres, Climate, Weather, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography
Ultraviolet Radiation Effects on the Optical Properties of Water-Dominated Exoplanet Hazes
Temperate sub-Neptune and terrestrial exoplanets could contain large inventories of water in various phases, such as water-dominated atmospheres or even oceans. Observations have shown that many exoplanets, including water worlds, […]
Posted inAstrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Status Report
The Atmosphere Of K2-18 b: The Role Of Hazes, Clouds And Photoelectrons
The atmospheric characterisation of temperate exoplanets is becoming accessible with JWST, providing a critical connection between Solar System planets and the more commonly observed hot-Jupiters.
Posted inAstronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report
Oxygenated False Positive Biosignatures in Mars-like Exoplanet Atmospheres
Oxygen is a well-studied biosignature. Studying potential abiotic pathways for O2 build-up in exoplanet atmospheres is essential for evaluating whether the detection of O2 would constitute a biosignature detection on […]
![[LEFT] Titan [RIGHT] Uranus -- NASA.gov](https://i0.wp.com/astrobiology.com/wp-content/uploads/2025/08/Photochemical-Haze-Formation.png?resize=1200%2C720&ssl=1)
Posted inAtmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Status Report, Titan, Uranus
Photochemical Haze Formation on Titan and Uranus: A Comparative Review
The formation and evolution of haze layers in planetary atmospheres play a critical role in shaping their chemical composition, radiative balance, and optical properties.
Posted inAstrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gas Giants, Imaging & Spectroscopy, Status Report, Titan, Venus
Measurement of Photochemical Haze Refractive Indices and Hygroscopicity: Influence of CO2 in CH4/H2S/N2 Mixtures
Atmospheric organic hazes are widespread across various planetary bodies and have significant effects on both the surface and atmosphere. In this study, we investigate the optical and hygroscopic properties of […]
Posted inAstrochemistry, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Habitable Zones, Ice Giant, Icy Worlds, Imaging & Spectroscopy, Status Report
The Radiative Effects of Photochemical Hazes on the Atmospheric Circulation and Phase Curves of Sub-Neptunes
Measuring the atmospheric composition of hazy sub-Neptunes like GJ 1214 b through transmission spectroscopy is difficult because of the degeneracy between mean molecular weight and haziness.