Benjamin Jacobsen nýggja grein í “The Astrophysical Journal”
Í nýggjastu útgávuni av vísindaliga tíðarritinum "The Astrophysical Journal” hevur Benjamin Jacobsen, Ph.D., eina grein við heitinum "Formation of the Short-Lived Radionuclide 36Cl in the Protoplanetary Disk During Late-Stage Irradiation of a Volatile-Rich Reservoir" Útgávan er júst send til prentingar.
Enskur samandráttur av greinini:
Short-lived radionuclides (SLRs) in the early solar system provide fundamental insight into protoplanetary disk evolution. We measured the 36Cl-36S-isotope abundance in wadalite (μm), a secondary chlorine-bearing mineral found in calcium-aluminum-rich inclusions (CAIs) in the Allende CV chondrite, to decipher the origin of the SLR 36Cl (τ 1/2 ~ 3 × 105 yr) in the early solar system. Its presence, initial abundance, and the noticeable decoupling from 26Al raise serious questions about the origin of SLRs. The inferred initial 36Cl abundance for wadalite, corresponding to a 36Cl/35Cl ratio of (1.81 ± 0.13) × 10–5, is the highest 36Cl abundance ever reported in any early solar system material. The high level of 36Cl in wadalite and the absence of 26Al (26Al/27Al ≤ 3.9 × 10–6) in co-existing grossular (1) unequivocally support the production of 36Cl by late-stage solar energetic particle irradiation in the protoplanetary disk and (2) indicates that the production of 36Cl, recorded by wadalite, is unrelated to the origin of 26Al and other SLRs (10Be, 53Mn) recorded by primary minerals of CAIs and chondrules. We infer that 36Cl was largely produced by irradiation of a volatile-rich reservoir in an optically thin protoplanetary disk adjacent to the region in which the CV chondrite parent asteroid accreted while the Sun was a weak T Tauri star. Subsequently, 36Cl accreted into the Allende CV chondrite together with condensed water ices.
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Benjamin Jacobsen, vardi í 2009 Ph.D ritgerðina "Chronology and Short-Lived Radionuclide Inventory of the Earliest Solar System Solids: Isotope Investigation of Calcium-Aluminum-Rich Inclusions from the Allende Meteorite" við University of California. Benjamin Jacobsen arbeiðir í dag á University of California, Davis, Department of Geology.
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