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The “Aerogel” Model for the Origin of the Short-Lived Radionuclides in the Early Solar System

The “Aerogel” Model for the Origin of the Short-Lived Radionuclides in the Early Solar System. Steve Desch, Nicolas Ouellette, Jeff Hester and Laurie Leshin Arizona State University. The Early Solar System held Short-Lived Radionuclides.

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The “Aerogel” Model for the Origin of the Short-Lived Radionuclides in the Early Solar System

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  1. The “Aerogel” Model for the Origin of the Short-Lived Radionuclides in the Early Solar System Steve Desch, Nicolas Ouellette, Jeff Hester and Laurie Leshin Arizona State University

  2. The Early Solar System held Short-Lived Radionuclides 41Ca (t1/2 = 0.1 Myr) 36Cl (t1/2 = 0.3 Myr) 26Al (t1/2 = 0.7 Myr) 10Be (t1/2 = 1.5 Myr) 60Fe (t1/2 = 1.5 Myr) 53Mn (t1/2 = 3.7 Myr) 107Pd (t1/2 = 6.5 Myr) 182Hf (t1/2 = 9 Myr) 129I (t1/2 = 16 Myr) 60Ni 61Ni Tachibana & Huss (2003) ApJ 588,L41 56Fe 61Ni

  3. Only Plausible Explanation for the 60Fe: A Nearby Supernova 60Fe / 56Fe ~ 5 x 10-7(Tachibana & Huss 2003; Huss & Tachibana2004) • Background levels of 60Fe: 60Fe/56Fe << 10-9(Harper 1996) • Nuclear reactions caused by proto-solar flares: < 10-9(Lee et al 1998; Leya et al 2003) • Passing AGB star: 60Fe / 56Fe ~ 10-7, but highly improbable: P << 10-6(Kastner & Myers 1994) • Nearby Supernova: 60Fe / 56Fe ~ 10-6(Wasserburg et al. 1998; Meyer & Clayton 2000) Sun HAD to be born within a few parsecs of a supernova!

  4. Supernova Probably < 1 pc Away: Radionuclides in supernova ejecta carried by dust grains that implant themselves in Sun’s protoplanetary disk like aerogel (but also evaporate) ~0.2pc disks 1Ori C: imminent supernova

  5. Summary • Meteorites show early solar system definitely had live 60Fe • Only plausible source of the 60Fe is a nearby supernova • Sun therefore formed in association with massive stars / H II region • Early Solar System probably just like disks in Orion Nebula (and was greatly affected by the environment) • Radionuclides in supernova grains probably lodged in our disk like aerogel: explains radionuclide abundances well if < 0.3 pc away (Desch & Ouellette, in preparation) • Disks can probably survive supernova if > 0.1 - 0.3 pc away (Chevalier 2000; Desch & Ouellette, in preparation)

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