snow line Archives - Astrobiology

Carbon isotope ratio as a function of the semi-major axis for young, directly-imaged companions. Measurements in the HR 8799 system for planets e, b, and c (Ruffio et al. 2026) are shown with squares and connected with a dotted line. The other measurements are for HD 984 b (Costes et al. 2024), GQ Lup b (González Picos et al. 2025b), VHS 1256 b (Gandhi et al. 2023), YSES 1 b (Zhang et al. 2024), AB Pic b (Gandhi et al. 2025), and DH Tau b and HIP 79098 b (Xuan et al. 2024a). The present-day local ISM (12C/13C = 68±14; Milam et al. 2005) and solar photospheric value (12C/13C⊙ = 91.4 ± 1.3; Lyons et al. 2018) are overlaid. The horizontal line spans the typical CO snow-line location for a solar-type host star (22–36 au). For stars hotter than the Sun, the CO snow line is expected at distances greater than 30 au, so β Pic b is located interior to the CO snow line. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Interstellar, Status Report

The Carbon Isotope Ratio Of β Pic b With High-resolution Spectroscopy

by Keith CowingJune 13, 2026June 13, 2026

Isotopic ratios trace the formation and evolution of planets and link their atmospheres to the chemistry of their natal protoplanetary discs.

Water planets may be rare -- NASA

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Press Release

Exoplanets Are Not Water Worlds

by Keith CowingSeptember 19, 2025

An exoplanet orbiting a dwarf star 124 light-years from Earth made headlines around the world in April 2025. Researchers at the University of Cambridge reported that planet K2-18b could be […]

Cartoon explaining the mechanism behind the formation of self-sustaining vortices at the temperature plateau at water snow region. The temperature substructure gives rise to marginal mismatch in the gas accretion rates, seeding the initial perturbation in gas surface density. The dust is attracted towards the resulting pressure maximum, which in turn lowers the local dust-dependent viscosity. This in turn causes a bottleneck to angular momentum transport, amplifying the perturbation in gas and thus, leading to positive feedback loop. In a one-dimensional disk, such a feedback leads to viscous ring instability (VRI), forming multiple concentric rings. In two-dimensional simulations, the gradient of gas surface density eventually becomes sharp enough to trigger Rossby wave instability and vortices are formed. The positive feedback responsible for VRI contributes towards stability of formed vortices. -- astro-ph.EP

Astrochemistry, Astrogeology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

Dust-driven Vortex Cascades Originating At Water Snow Region: A Pathway To Planetesimal Formation

by Keith CowingApril 29, 2025April 29, 2025

The origin of observed planetary systems, including our solar system, as well as their diversity is still an open question.

Orbit-integrated water sublimation of 81P facets. The left and right figures preferentially show the explored northern and the unexplored southern side, respectively. -- astro-ph.EP

Astrogeology, Comets and Asteroids, Icy Worlds, Mapping, Geodesy, Cartography, Bathymetry, Status Report

Enlargement of Depressions on Comet 81P/Wild 2: Constraint Based on 30-year Cometary Activity in the Inner Solar System

by Keith CowingDecember 18, 2024December 18, 2024

Context. The Stardust flyby mission to Jupiter-family comet (JFC) 81P/Wild 2 (hereafter, 81P) captured its dense quasicircular depressions. Nevertheless, the formation mechanism remains a subject of ongoing debate.

Overview of our models for gas disk and particles evolution in different disk regions. The blue and yellow particles represent silicates with and without refractory carbon. The light blue particles represent icy pebbles. The pink particles show the oxygen atoms which are formed by the destruction of oxygen molecules because of the FUV radiation which is described as red arrows. The light blue dashed line is the snow line. Icy pebbles enclosing many small silicates drift to the snow line (blue dashed line) from the outer region. Orange upper and lower layers are FUV-exposed regions, where oxygen atoms exist. -- astro-ph.EP

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Habitable Zones, Imaging & Spectroscopy, Interstellar, Status Report

Effect of Different Stickiness Between Icy and Silicate Particles on Carbon Depletion in Protoplanetary Disks

by Keith CowingOctober 12, 2024October 12, 2024

Earth and other rocky bodies in the inner Solar System are significantly depleted in carbon compared to the Sun and interstellar medium (ISM) dust.

An SwRI-led team used NASA’s Webb telescope, shown in the bottom right corner of this illustration, to confirm the presence of hydrated minerals on the surface of Psyche, a massive and heavily metallic body in the main asteroid belt. These findings suggest a complex history for this interesting asteroid, which many scientists think could be the remnant core of a protoplanet, including impacts with hydrated asteroids. -- SWRI

Astrochemistry, Astrogeology, Biosignatures & Paleobiology, Comets and Asteroids, Imaging & Spectroscopy, Press Release

Evidence Of Hydration Has Been Found On Metallic Asteroid Psyche

by Keith CowingAugust 14, 2024August 14, 2024

Using data from NASA’s James Webb Space Telescope, a Southwest Research Institute-led team has confirmed hydroxyl molecules on the surface of the metallic asteroid Psyche. The presence of hydrated minerals […]

Distribution of eccentricities for all planets more massive than 0.3 MJ interior to the snow line (left panels) and exterior to the snow line (right panels). For the top two panels, both the shade and the size of the plotted data are logarithmically proportional to the planet mass, where dark green indicates a low mass and light green indicates a high mass. The bottom two panels show the histograms of the eccentricity data appearing in the top two panels. -- astro-ph.EP

Astrochemistry, Astrogeology, Exoplanets, -moons, -comets, Gas Giants, Habitable Zones, Status Report, Water/Hycean Worlds & Oceanography

Eccentricity Distribution Beyond the Snow Line and Implications for Planetary Habitability

by Keith CowingFebruary 7, 2024February 7, 2024

A fundamental question in the study of planetary system demographics is: how common is the solar system architecture?

An artist's concept of the snow line in TW Hydrae showing water ice covered dust grains in the inner disc (4.5–30 astronomical units, blue) and carbon monoxide ice covered grains in the outer disc (>30 astronomical units, green). The transition from blue to green marks the carbon monoxide snow line. The snow helps grains of dust to adhere to each other by providing a sticky coating, which is essential to the formation of planets and comets. Due to the different freezing points of different chemical compounds, different snow lines can be found at various distances from the star. Credit: B. Saxton & A. Angelich/NRAO/AUI/NSF/ALMA (ESO/NAOJ/NRAO)

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Press Release

Snow In An Infant Planetary System

by Keith CowingJuly 18, 2013September 19, 2025

A snow line has been imaged in a far-off infant planetary system for the very first time. The snow line, located in the disc around the Sun-like star TW Hydrae, […]