![Illustration of the different size averages for Renazzo (after the data of Ebel et al. (2024)) on a back-scattered electron image of polished section 719sp3 of the Muséum national d’Histoire naturelle collection (Jacquet et al., 2012).-- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Chondrule.png?resize=1200%2C720&ssl=1)
[astro-ph.EP] Chondrule sizes are an important discriminant of chondrite groups and chondrule formation theories. Yet most studies report 2D sizes without attempting the somewhat tedious corrections to 3D proposed in […]
Astrogeology
Posted inMars
Sulfate Deposits On Iani Chaos On Mars
[NASA/JPL-Caltech/UArizona] This HiRISE image shows light-toned layered deposits within Iani Chaos. Many of the same deposits occur within the depressions of Iani Chaos, as well as several nearby similar regions […]
![Final semi-major axes and masses for all objects produced in simulations with regular disks. The left panel shows objects produced in disks with low C/O ratios and the right one shows planets in high C/O ratio disks. The dash-dotted line shows the initial mass of planestesimals in our simulations while the dotted line shows the initial mass of planetary embryos. We consider planets to be anything at or above the initial embryo mass, fragments to be anything below the initial planetesimal mass, and planetesimals to be any object at or above the initial planetesimal mass but below the initial embryo mass. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Correlations.png?resize=1200%2C719&ssl=1)
Posted inExoplanets, -moons, -comets
Correlations Between The Carbon-to-Oxygen Ratio and the Orbital and Physical Properties of Exoplanets
[astro-ph.EP] Studies suggest that protoplanetary disks around stars with high carbon-to-oxygen (C/O) ratios can produce terrestrial planets with carbon-dominated compositions instead of silicon-dominated ones.
![Median protoplanetary disk composition predicted by the chemical model at different metallicities [Fe/H]. LEFT: Median overall composition. RIGHT: Median refractory composition. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/On-the.png?resize=1200%2C719&ssl=1)
Posted inInterstellar
On The Compositions Of Interstellar Objects
[astro-ph.EP] As physical samples of distant planetary systems, the compositions of interstellar objects (ISOs) should correlate with the properties of their diverse parent stars.
![Chemical clock relations for planet-hosting solar analogs, showing abundance ratios as a function of stellar age for [Y/Mg], [Y/Al], [Ba/Mg], [Ba/Al], [Sr/Mg], and [Y/(Mg+Al)/2]. Data points are color-coded by metallicity ([Fe/H]). Black lines show best-fit linear relations derived using Deming regression, accounting for uncertainties in both variables, and shaded regions indicate 1σ confidence intervals. All abundance ratios show statistically significant correlations with stellar age. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Planets-Around.png?resize=1200%2C720&ssl=1)
Posted inExoplanets, -moons, -comets
Planets Around Solar Twins/Analogs (PASTA) III: Chemical Clock Relations in Planet-Hosting Solar Analogs
[astro-ph.EP] Context. Abundance ratios between elements synthesized on different nucleosynthetic timescales provide empirical chemical clocks for estimating stellar ages, but robust calibrations require homogeneous samples with precise stellar parameters and […]
Posted inImpact events
JWST Studies Of Planet-shattering Collisions
[ESA]. In the early history of our Solar System, a Mars-sized object called Theia smashed into the infant Earth, vapourising massive amounts of rock and blasting it into space. Some […]
Posted inMars
Following Ancient Rain Toward The Origins Of Life On Mars
[Tohoku University] The Mars we know today is a cold, dry world of dust and rocks. However, around 3.8-3.6 billion years ago, it may have looked very different. Geological and […]
Posted inTitan
Flow Dynamics Of Cryolava Or Impact Melt On Titan’s surface
[astro-ph.EP] Titan, a unique body in the solar system, resembles a life-size Miller-Urey experiment where pockets of liquid water might interact with abundant organic matter.
![Visual abstract -- [Journal of the American Chemical Society]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Nonequilibrium.jpg?resize=1200%2C716&ssl=1)
Posted inAstrochemistry
Nonequilibrium Formation of Pyridine (C5H5N) in Interstellar Ice Analogs: Implications for Biorelevant Nitrogen Heterocycles in Ryugu and Bennu
[Journal of the American Chemical Society] Biorelevant nitrogen heterocycles, including the five canonical nucleobases found in RNA and DNA, have recently been identified in samples returned from the carbonaceous asteroids […]
Posted inAstrogeology
Our Solar System Chose Fire Over Ice To Build Its First Bodies
[Yale University] When the solar system first took up the task of building solid bodies — such as planets, moons, and protoplanets — it basically had a choice between two […]