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A key stage in planet formation is the evolution of a gaseous and magnetized solar nebula. However, the lifetime of the nebular magnetic field and nebula are poorly constrained. We present paleomagnetic analyses of volcanic angrites demonstrating that they formed in a near-zero magnetic field (<0.6 microtesla) at 4563.5 ± 0.1 million years ago, ~3.8 million years after solar system formation. This indicates that the solar nebula field, and likely the nebular gas, had dispersed by this time. This sets the time scale for formation of the gas giants and planet migration. Furthermore, it supports formation of chondrules after 4563.5 million years ago by non-nebular processes like planetesimal collisions. The core dynamo on the angrite parent body did not initiate until about 4 to 11 million years after solar system formation.
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http://dx.doi.org/10.1126/science.aaf5043 | DOI Listing |
Sci Rep
August 2025
Turin Astrophysical Observatory, National Institute of Astrophysics (INAF), Pino Torinese, Italy.
Chondrules are spherical or subspherical particles of crystallized or partially crystallized liquid silicates that constitute large-volume fractions of most chondritic meteorites. Chondrules typically range mm in size and solidified with cooling rates of , yet these characteristics prove difficult to reconcile with proposed formation models. We numerically show that collisions among planetesimals containing volatile materials naturally explain both the sizes and cooling rates of chondrules.
View Article and Find Full Text PDFPhys Rev Lett
July 2025
Centro de Astrobiologa (CSIC-INTA), Departamento de Astrofsica, Carretera Torrejon a Ajalvir km 4, 28850 Torrejon de Ardoz, Spain.
The ∼60 000 solar-mass (M_{⊙}) star cluster R136 (NGC 2070) in the Tarantula Nebula in the Large Magellanic Cloud is the host of at least 55 massive stars (M≳10M_{⊙}) which move away from the cluster at projected velocities ≥27.5 km/s. The origin of the high velocities of such runaway stars have been debated since the 1960s, resulting either from dynamical ejections or from supernova explosions.
View Article and Find Full Text PDFNat Commun
July 2025
School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA.
Chondrules are a characteristic feature of primitive Solar System materials and are common in all primitive meteorites except the CI-chondrites. They are thought to form owing to melting of solid dust aggregates by energetic processing within the solar nebula and thus record fundamental processes within protoplanetary disks. We report the discovery of abundant altered microchondrules (>350 ppm) with modal sizes of 6-8 µm within sample A0180 from C-type asteroid Ryugu.
View Article and Find Full Text PDFSci Adv
May 2025
Human Spaceflight Technology Directorate, Japan Aerospace Exploration Agency, 2-1-1, Sengen, Tsukuba-shi, Ibaraki 305-8505, Japan.
Millimeter-sized silicate spherules embedded in primitive meteorites, namely, "chondrules," are the primary solid component of the early solar nebula. They exhibit distinctive solidification textures, formed through rapid cooling from a molten state. The formation conditions of these textures have primarily been inferred on the basis of dynamic crystallization experiments; however, the theoretical verification of the solidification process has been largely neglected.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
May 2025
Institut Origine et Evolution, Muséum National d'Histoire Naturelle, Sorbonne Université, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie - UMR 7590 CNRS, Paris 75005, France.
Contrary to all terrestrial rocks, planets and meteorites exhibit oxygen isotope variations decorrelated with the mass difference of their atomic nuclei. It has been proposed that, in the protosolar nebula (PSN), these variations could result from mass independent isotopic fractionation (MIF) either during specific chemical reactions similar to those responsible for the formation of ozone in the Earth's atmosphere or during ultraviolet (UV)-photolysis of carbon monoxide (CO) gas in the PSN. However, these potential chemical MIF reactions (Chem-MIFs) are not identified in conditions close to the PSN, and there is no experimental demonstration that large MIF signature can be transferred to solids forming in the PSN.
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