![Fraction of different types of planets formed around stars in a grid with varying [Fe/H] and M∗. In order to form giant planets and super-Earths we require either a high metallicity or a high stellar mass. Further, water-rich planets are more common around stars with higher metallicities and stellar mass as these stars can sustain a high enough pebble flux outside the water ice line to form water-rich planets there. Earth-mass planets dominate for all metallicities and stellar masses as they do not require a high pebble flux in order to form. -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2023/09/planetformation.png?resize=1200%2C719&ssl=1)
As stellar compositions evolve over time in the Milky Way, so will the resulting planet populations. In order to place planet formation in the context of Galactic chemical evolution, we […]
astrogeology
![Compositional evolution of lava planets interiors from an initial homogeneous molten state. Chemical fractionation occurs during planetary solidification because rock-forming elements do not have the same affinities for liquid and solid phases. For instance, FeO prefers to remain in the liquid rather than being incorporated in the solids. (a and b) Initial conditions. The magma ocean is well mixed and nearly entirely molten. The composition of the magma ocean corresponds to the bulk planet’s composition, i.e., 6% of FeO (BSE composition). This is the global magma ocean stage. (c and d) Onset of the mushy stage. The MO crystal fraction is about 50%. Iron-rich solids accumulate in the deep mantle. The most liquid part of the planet shows a FeO content of 10%. (e-f) End of the mushy stage. The FeO concentration of the MO reaches its maximum, 12%. (g-h) Solid-state stage. The iron-rich shallow magma ocean has been buried in the deep mantle. The day-side shallow magma ocean has a concentration of about about 2%. The solid mantle is strongly layered. Iron-rich solids remelts to form a basal magma ocean. -- astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2023/08/Lava-planets.png?resize=1200%2C720&ssl=1)
Posted inAstrogeology, Biogeochemical Cycles & Geobiology, Caves, Craters, Mountains, Subsurface, Lava Tubes, Exoplanets, -moons, -comets, Io, Status Report
Lava Planets Interior Dynamics Govern The Long-term Evolution Of Their Magma Oceans
Lava planets are rocky exoplanets that orbit so close to their host star that their day-side is hot enough to melt silicate rock. Their short orbital periods ensure that lava […]
Posted inAstrochemistry, Astrogeology, Exoplanets, -moons, -comets, Status Report
Close-in Ice Lines And The Super-stellar C/O ratio In Discs Around Very Low-mass Stars
The origin of the elevated C/O ratios in discs around late M dwarfs compared to discs around solar-type stars is not well understood. Here we endeavour to reproduce the observed […]
![Cross plots of log(fO2) expressed as ∆FMQ, resulting from pMELTS calculations, shown at 1 GPa (top) and 4 GPa (bottom) and 1373.15 K. From left to right, columns show the dependence of ∆FMQ on bulk mantle Mg/Si, Al/Si, stellar metallicity [Fe/H]⋆, and the total refractory oxygen present in the mantle, Orock (i.e., a sum over oxygen in all metal oxides). Each point (N = 1198) represents a bulk mantle composition (Ca-Na-Fe-Mg-Al-Si-O-Ti) inferred for a planet-hosting star in the Hypatia Catalog, assuming Fe3+/ΣFe = 3% and Femantle/(Fecore + Femantle) = 12%. Points are coloured by the Fe2O3 wt.% composition of orthopyroxene (opx). Histograms of the ∆FMQ distribution are projected on the y-axis. -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2023/08/Mineralogical.png?resize=1200%2C719&ssl=1)
Posted inAstrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Status Report
A Mineralogical Reason Why All Exoplanets Cannot Be Equally Oxidising
From core to atmosphere, the oxidation states of elements in a planet shape its character. Oxygen fugacity (fO2) is one parameter indicating these likely oxidation states.
Posted inAstrochemistry, Astrogeology, Status Report
Isotopic Enrichment Of Planetary Systems From Asymptotic Giant Branch Star
Short-lived radioisotopes, in particular 26-Al and 60-Fe, are thought to contribute to the internal heating of the Earth, but are significantly more abundant in the Solar System compared to the […]
Posted inAstrochemistry, Astrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Status Report
The Chemical Evolution Of The Solar Neighbourhood For Planet-hosting Stars
Theoretical physical-chemical models for the formation of planetary systems depend on data quality for the Sun’s composition, that of stars in the solar neighbourhood, and of the estimated “pristine” compositions […]
Posted inAstrochemistry, Astrogeology, Biosignatures & Paleobiology, Comets and Asteroids, Imaging & Spectroscopy, Meteorites & Asteroids, Status Report
Analysis of CN Emission As A Marker Of Organic Compounds In Meteoroids Using Laboratory Simulated Meteors
Fragments of small solar system bodies entering Earth’s atmosphere have possibly been important contributors of organic compounds to the early Earth.
Posted inArtemis & Lunar Exploration, Astrochemistry, Astrogeology, Moon, Status Report
Discovery Of A New Lunar Mineral Rich In Water And Ammonium In Lunar Soils Returned By Chang’e-5 mission
The origin and distribution of lunar water are among the most important issues in understanding the earth-moon system. After more than half a century of laboratory research and remote detection, […]
Posted inAstrochemistry, Astrogeology, Meteorites & Asteroids, Status Report
Condensation Calculations In Planetary Science And Cosmochemistry
Cool a piece of the Sun to 1000 K at one millibar pressure to yield a mineral assemblage consistent with those found in the most primitive meteorites. This is an […]
Posted inAstrochemistry, Astrogeology, Comets and Asteroids, Meteorites & Asteroids, Status Report
Abundance, Major Element Composition and Size of Components and Matrix in CV, CO and Acfer 094 Chondrites
The relative abundances and chemical compositions of the macroscopic components or “inclusions” (chondrules and refractory inclusions) and fine-grained mineral matrix in chondritic meteorites provide constraints on astrophysical theories of inclusion […]