astrogeology Archives - Page 102 of 108 - Astrobiology

‘Oumuamua -- Illustration by Samuel Cabot

Astrochemistry, Astrogeology, Astronomy & Telescopes, Comets and Asteroids, Interstellar, Meteorites & Asteroids, Panspermia, Press Release, Space Weather & Heliophysics

X-rays May Tell Us More About The Origins Of Visiting Space Rocks

by Keith CowingOctober 14, 2023October 14, 2023

A research team led by a Yale astronomer has some advice for our next close encounter with a wandering, interstellar object. Check its X-rays on the way out. Since 2017, […]

Schematic illustration of transport and mixing between different isotopic reservoirs during growth of Mars and Earth. Mars was born near the inner edge of the main asteroid belt, in between the ℰ and � reservoirs. It started accreted an equal mixture of both planetesimals (A) but progressively accreted more ℰ material as it migrated inwards into the ℰ region by type I migration (B). During those times, carbonaceous asteroids from the outer solar system were scattered inwards by the giant planets, but interaction with nebular gas led to their implantation into the outer main belt. Larger carbonaceous objects were less subjected to gas drag and were able to penetrate in the inner solar system. Earth grew later primarily from ℰ -type embryos (C). Several tens of millions of years after solar system formation, one or several interloper carbonaceous embryos implanted in the inner disk during the first phase were stochastically accreted by the Earth (D). -- astro-ph.EP

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Mars, Status Report

Bayesian Inference On The Isotopic Building Blocks Of Mars And Earth

by Keith CowingSeptember 30, 2023September 30, 2023

Isotopic anomalies provide a means of probing the materials responsible for the formation of terrestrial planets. By analyzing new iron isotopic anomaly data from Martian meteorites and drawing insights from […]

The sample return capsule from NASA’s OSIRIS-REx mission is seen shortly after touching down in the desert, Sunday, Sept. 24, 2023, at the Department of Defense's Utah Test and Training Range.

Astrochemistry, Astrogeology, Away Teams & Field Reports, Biosignatures & Paleobiology, Comets and Asteroids, Missions & Hardware, Planetary Protection & Biosafety, Press Release

The OSIRIS-REx Samples From Bennu Have Landed On Earth

by Keith CowingSeptember 25, 2023September 25, 2023

After years of anticipation and hard work by NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification and Security – Regolith Explorer) team, a capsule of rocks and dust collected from asteroid […]

Abundance profiles for selected condensates. Left panel: iron-bearing condensates, middle panel: magnesium and calcium species, right panel: Na and K condensates. The solid lines refer to the equilibrium condensation calculations. Dashed lines indicate the results for the rainout approximation. -- astro-ph.EP

Astrochemistry, Astrogeology, Brown Dwarfs, Exoplanets, -moons, -comets, Status Report

FastChem Cond: Equilibrium Chemistry with Condensation and Rainout for Cool Planetary and Stellar Environments

by Keith CowingSeptember 6, 2023September 6, 2023

Cool astrophysical objects, such as (exo)planets, brown dwarfs, or asymptotic giant branch stars, can be strongly affected by condensation. Condensation does not only directly affect the chemical composition of the […]

A training model of the sample return capsule is seen is seen during a drop test in preparation for the retrieval of the sample return capsule from NASA's OSIRIS-REx mission, Wednesday, Aug. 30, 2023 -- NASA

Astrochemistry, Astrogeology, Biosignatures & Paleobiology, Comets and Asteroids, Meteorites & Asteroids, Missions & Hardware, Planetary Protection & Biosafety, Press Release

NASA Completes Last OSIRIS-REx Test Before Asteroid Sample Delivery

by Keith CowingSeptember 5, 2023September 5, 2023

A team led by NASA in Utah’s West Desert is in the final stages of preparing for the arrival of the first U.S. asteroid sample – slated to land on […]

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

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

Planet Formation Throughout The Milky Way: Planet Populations In The Context Of Galactic Chemical Evolution

by Keith CowingSeptember 1, 2023September 1, 2023

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 […]

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]

Astrogeology, 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

by Keith CowingAugust 31, 2023August 30, 2023

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 […]

Temporal evolution of the gas disc C/O ratio (normalised to the stellar value) as a function of distance from the star, stellar mass (left to right), and disc viscosity (top and bottom rows). Ice lines are marked by vertical dashed white lines, and solid black lines indicate an absolute C/O ratio of 1. The carbon line is absent in the top leftmost panel because it is located inside 0.1 AU. Outside the CO ice line (Tdisc ≤ 20 K; white region in the subplots), all chemical species are assumed to be frozen in the solid phase. -- astro-ph.EP

Astrochemistry, Astrogeology, Exoplanets, -moons, -comets, Status Report

Close-in Ice Lines And The Super-stellar C/O ratio In Discs Around Very Low-mass Stars

by Keith CowingAugust 29, 2023August 29, 2023

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

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Status Report

A Mineralogical Reason Why All Exoplanets Cannot Be Equally Oxidising

by Keith CowingAugust 21, 2023August 21, 2023

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.

Gaia DR3 colour–absolute–magnitude diagram of stars within 100 pc of NGC 2264 identifying RW (>30 km s−1 , shown in red) and WW (>5 km s−1 , shown in blue) stars. The WW at the top right of the giant branch (Gaia DR3 3131012157848982272) is a likely AGB star. -- astro-ph.EP

Astrochemistry, Astrogeology, Status Report

Isotopic Enrichment Of Planetary Systems From Asymptotic Giant Branch Star

by Keith CowingJuly 27, 2023July 27, 2023

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 […]