water iceline Archives

Gas-phase C/O ratio as a function of distance to the star for the two different values of the stellar mass (M∗ = 1, 0.1 M⊙) and three values of the turbulent viscosity (α = 10−2 , 10−3 , 10−4 ). The horizontal dashed grey line represents the initial C/O ratio. The sublimation lines of the main species contributing to the C/O ratio are indicated with vertical lines. We see that the evolution of the gas-phase C/O ratio does not change significantly with varying disc turbulence (α > 10−3 ) and stellar mass. However, in the α = 10−4 case, where the pebble flux is intense and diffusion is slow, the variations in gas-phase C/O ratio are greater. Once the pebble flux runs out, viscous flows govern the evolution of the gas-phase C/O ratio, leading to differences depending on stellar mass. -- astro-ph.EP

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Interstellar, Status Report

Burned To Ashes: How the Thermal Decomposition of Refractory Organics in the Inner Protoplanetary Disc Impacts the Gas-phase C/O Ratio

by Keith CowingMay 28, 2025May 28, 2025

The largest reservoir of carbon in protoplanetary discs is stored in refractory organics, which thermally decompose into the gas-phase at the organics line, well interior to the water iceline.

Detrended TESS (top row) and CHEOPS (bottom row) light curves, phase-folded to the orbital periods of HIP 29442 b (left), c (middle) and d (right). The coloured points show the 30-min binned data, the solid black lines show the best-fit transit models. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Gas Giants, Icy Worlds, Imaging & Spectroscopy, Press Release, Water/Hycean Worlds & Oceanography

Unveiling the Internal Structure And Formation History Of The Three Planets Transiting HIP 29442 (TOI-469) With CHEOPS

by Keith CowingJune 28, 2024June 28, 2024

Multiplanetary systems spanning the radius valley are ideal testing grounds for exploring the proposed explanations for the observed bimodality in the radius distribution of close-in exoplanets. One such system is […]

water iceline

Burned To Ashes: How the Thermal Decomposition of Refractory Organics in the Inner Protoplanetary Disc Impacts the Gas-phase C/O Ratio

Unveiling the Internal Structure And Formation History Of The Three Planets Transiting HIP 29442 (TOI-469) With CHEOPS

Dragonfly Titan Astrobiology Droid Clears Key Tests

Expedition Led By MBARI Researchers Reveals A Remarkable, And Rare, Form Of Deep-sea Hydrothermal Vents

SwRI Study Found Primordial Mini-moons May Explain Meteorite Composition

The Galactic Centre G+0.633-0.0604 Molecular Cloud: A New Astrochemical Gold Mine. I. Gas Physical Properties

Researchers Confirm The Cause Of Earth’s Biggest Mass Extinction