chondrule Archives

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]

Chondrule Size Averaging In Two And Three Dimensions

by Keith CowingOctober 5, 2026October 5, 2026

[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 […]

Ni, Cu and Zn elemental maps of three chondrules from Paris, that show microspherule regions partitioned by zones enriched in siderophile elements (i.e., Fe, Ni, Co, Cu; pink arrows). The color bars reflect μg/g concentrations of the elements. While in BSE mode and lithophile element space, these would appear as single ~300 μm diameter chondrules, they represent aggregates of ~100 μm grape-bunch chondrules (pink spheres), where these microchondrules contained metal-rich rims. -- [astro-ph.EP]

Astrogeology

Chondrule Formation In The Outer Disk From The Primary Three-dimensional Chemical Composition Of CM Chondrules

by Keith CowingAugust 16, 2026August 16, 2026

[astro-ph.EP] Chondrules and their associated fine-grained rims record key processes in the early protoplanetary disk, yet the links between chondrule chemistry, morphology, and matrix complementarity remain poorly constrained.

Final size of protoplanets after 2 My of Hill regime pebble accretion, for different Stokes numbers of silicate and metal pebbles. The plot shows protoplanet mass relative to Earth (white contours and shading) and protoplanet metal mass fraction (black contours) as functions of the Stokes numbers of metal and silicate pebbles. The red dots represent chondrule and metal grain Stokes numbers based on measured size and density in the Kelly (K), Bjurbole (B), and Hammond Down (H) chondrites, respectively. The turquoise box indicates the implied range of pebble Stokes numbers, including individual metal grains and metal grain aggregates. The red contour corresponds to an Earth-like (Fe+Ni)/Si mass ratio of 2.06 and defines our preferred models with protoplanetary masses between 0.35 and 0.7 Earth masses. -- astro-ph.EP

Astrochemistry, Astrogeology, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Status Report

Building Earth With Pebbles Made Of Chondritic Components

by Keith CowingJuly 23, 2025July 23, 2025

Pebble accretion provides new insights into Earth’s building blocks and early protoplanetary disk conditions.

Protoplanetary Disk -- Grok via Astrobiology.com

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

Protoplanetary Cores Drove Chondrule Formation

by Keith CowingMarch 24, 2025March 24, 2025

Chondrules are small spherical objects that formed at high temperatures early in the history of the Solar System. The key compositional characteristics of chondrules may be well explained by high […]

Chondrules exhibiting complex structures with multiple zoning and rims, which is indicative of multiple melting events. A) Chondrule from the LAP 02342 CR2 chondrite with a primary and secondary shell and a surrounding igneous rim, all separated by metal rims (from Rubin, 2010). B) Complex chondrule from CR2 chondrite Acfer 139 with four shells (s) and metal (m) rims (from Hobbart et al., 2015), with Si = red, Ca = green, 12 Fe = blue. Olivine in pyroxene-bearing layer S2 grew epitaxialy on olivine in pyroxene-free layer S1, the two separated by a thin layer M1 of numerous metal grains. -- astro-ph.EP

Astrochemistry, Astrogeology, Comets and Asteroids, Meteorites & Asteroids, Status Report

Is There A Genetic Relationship Between Chondrules And Matrix?

by Keith CowingSeptember 16, 2024September 16, 2024

Chondritic components such as chondrules and matrix are the key time capsules that can help us understand the evolution and dynamics of the protoplanetary disk from which the Solar System […]