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Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence

Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence. Planet Formation and Evolution: The Solar System and Extrasolar Planets Tübingen 1.-6.3.2009 M. Trieloff University of Heidelberg, Institute of Geosciences, Heidelberg, Germany.

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Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence

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  1. Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence Planet Formation and Evolution: The Solar System and Extrasolar Planets Tübingen 1.-6.3.2009 M. Trieloff University of Heidelberg, Institute of Geosciences,Heidelberg, Germany

  2. Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence • Astrophysical evidence: • Observations of protoplanetary discs (extrasolar) • Cometary evidence (early solar system): • Hale Bopp (IR observations) • Wild-2 dust returned by STARDUST (laboratory analyses) • Meteoritic evidence (early solar system asteroids): • Flash heated objects in chondrites: Chondrules and calcium,aluminum rich inclusions (CAIs)

  3. IR spectroscopy of protoplanetary disks: Mg silicates olivine+pyroxene –crystalline fraction higher in inner disks (van Boekel et al. 2004) 40 +- 20% 15 +- 10% 55 +- 25% 10 +- 5% 40 +- 15% 95 +- 10%

  4. Crystalline fractions in some outer disks considerable, similar to solar system comets • (Wooden et al., 2000) • Dust processing in disks and radial mixing into outer disks IR spectroscopy of protoplanetary disks: Mg silicates olivine+pyroxene –crystalline fraction higher in inner disks (van Boekel et al. 2004) 10 +- 5% 40 +- 20% 55 +- 25% 95 +- 10%

  5. Cometary grains from comet Wild-2 returned by the STARDUST mission Refractory forsterite grain from STARDUST collector CAI „Inti“ Silicates (Olv, Px, Fs), glass, Fe-Ni sulfide, refractory minerals (An,Di,Sp), CAI: Inti No phyllosilicates and carbonates in Wild-2 particles

  6. Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence • Astrophysical evidence: • Observations of protoplanetary discs (extrasolar) • Cometary evidence (early solar system): • Hale Bopp (IR observations) • Wild-2 dust returned by STARDUST (laboratory analyses) • Meteoritic evidence (early solar system asteroids): • Flash heated objects in chondrites: Chondrules and calcium,aluminum rich inclusions (CAIs) Indicator: High temperature processing (crystallinity, refractory rich)

  7. Meteorites: Fragments of small bodies in the solar system, the asteroids between Mars and Jupiter Inferred number of parent bodies is >100 (accretion to full-sized planet inhibited by early Jupiter?!) Innisfree

  8. Carbonaceous chondrites (CI, CM, CV, CO, …): (mild thermal/aqueous metamorphism) undifferentiated, e.g. preaccretional structures preserved • Chondrules 1400-1600 K • Ca,Al-rich inclusions 1800-2000 K • Fine grained matrix (volatile rich) <900 K undifferentiated, e.g. ‘cosmic’ Fe,Ni abundance Allende

  9. Metal abundance of chondrites: Origin from primitive, undifferentiated parent bodiesVariation of oxidation state and metal abundance: Origin from compositionally different parent asteroids Ordinary chondrites: H: high Fe L: Low Fe LL: Low total, low metallic Fe Enstatite chondrites Carbonaceous chondrites: named after main member CI (Ivuna) CM (Mighei) CV (Vigarano) CO (Ornans)

  10. Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence • Astrophysical evidence: • Observations of protoplanetary discs (extrasolar) • Cometary evidence (early solar system): • Hale Bopp (IR observations) • Wild-2 dust returned by STARDUST (laboratory analyses) • Meteoritic evidence (early solar system asteroids): • Flash heated objects in chondrites: Chondrules and calcium,aluminum rich inclusions (CAIs) Indicator: High temperature processing (crystallinity, refractory rich) High temperature processing of chondrules and CAIs: indicative of radial mixing?

  11. Nuth (2001) … some models assume the answer is YES

  12. … what about (abundant) chondrules? … fast cooling (100-2000 K / hour; e.g. former melt glass) … local flash heating (shock, lightning, planetary collisions) in the asteroid belt region? … do chronology and chemical complementarity allow large scale movements?

  13. CV3 Efremovka forsterite (high Mg) chondrules solar Mg-, Si-composition enstatite (intermediate Mg) solar Mg/Si-ratio matrix Chemical complementarity of chondrules and matrix in CV chondrites:Exemplified by Mg and Si (J. Wood, P. Bland, H. Palme)

  14. Chemical complementarity of chondrules and matrix in CR chondrites:Exemplified by Mg and Si (J. Wood, P. Bland, H. Palme)

  15. Matrix and chondrules of specific chondrites formed from Mg/Si= solar precursor material, and were not separated (e.g. by radial drift) before chondrite accretion  growth timescales short when compared to radial drift timescales CV chondrules CR chondrules 0 15 40 37 55 20 [% chondrules] CV matrix CR matrix

  16. What about isotope chronology of chondrule formation? 4564.7± 0.6 Ma (CR Acfer059;Amelin et al., 2002) • Chondrules 2-3 Ma age difference supported by 26Al-26Mg chronometry • Ca,Al-rich inclusions 4567.2± 0.6 Ma (U-Pb-Pb,CV Efremovka;Amelin et al., 2002) Allende

  17. Trapezium (Orion nebula) Short-lived nuclides in the early solar system and their half-lives: 26Al  26Mg (0.72 Ma)129I  129Xe (16 Ma)182Hf  182W (9 Ma)53Mn  53Cr (3.7 Ma)244Pu  fission (80 Ma)10Be  10B (1.5 Ma)41Ca  41K (0.1 Ma)60Fe  60Ni (1.5 Ma)… nucleosynthesis in mass-rich stars … or nuclear reactions due to solar irradiation (10Be) • ... injected into protoplanetary • disks (solar mass) • Radiometric dating • Planetesimal heating

  18. 26Al as tool for radiometric dating:26Al-26Mg ages of individual chondrules of different chondritic parent bodies (Kita, Nagahara, Russell, Mostefaoui etc.)

  19. 26Al as planetesimal heat source: Extent of heating as a function of 26Al content and accretion time after CAIs

  20. Mean 26Al-26Mg ages of chondrules of different chondritic parent bodies correlate with heating degree of parent bodies: stronger heated planetesimals have earlier formed chondrule populations

  21. Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence • Astrophysical evidence: • Observations of protoplanetary discs (extrasolar) • Cometary evidence (early solar system): • Hale Bopp (IR observations) • Wild-2 dust returned by STARDUST (laboratory analyses) • Meteoritic evidence (early solar system asteroids): • Flash heated objects in chondrites: Chondrules and calcium,aluminum rich inclusions (CAIs) Indicator: High temperature processing (crystallinity, refractory rich) NO (only possible if fast movement with micron dust) High temperature processing of chondrules: indicative of radial mixing? High temperature processing of CAIs: indicative of radial mixing?

  22. Zoned type B1 CAI from Leoville (CV) Fassait (Ti-rich diopside) Melilite Anorthite

  23. Condensation sequence of minerals in a cooling solar nebula: Ca,Al minerals important high temperature condensates Fe-Ni-metal Enstatite – MgSiO3 Gehlenite Ca2Al2SiO7 Fraction CI chondritic composition condensed Hibonite CaAl12O19 Spl Forsterite – Mg2SiO4 Cpx Albite Anorthite from: Davis & Richter 2005

  24. CAIs and refractory inclusions: • Rare(0.1% - 13%) • Carrier of 16O enrichment in carbonaceous chondrites • Slower cooling than chondrules (10 K / hour) • Resided 2-4 Ma in solar nebula • Independent chemical component

  25. Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence • Astrophysical evidence: • Observations of protoplanetary discs (extrasolar) • Cometary evidence (early solar system): • Hale Bopp (IR observations) • Wild-2 dust returned by STARDUST (laboratory analyses) • Meteoritic evidence (early solar system asteroids): • Flash heated objects in chondrites: Chondrules and calcium,aluminum rich inclusions (CAIs) Indicator: High temperature processing (crystallinity, refractory rich) NO (only possible if fast movement with micron dust) High temperature processing of chondrules: indicative of radial mixing? Good candidates High temperature processing of CAIs: indicative of radial mixing?

  26. Radial Mixing in the Early Solar System: Meteoritic and Cometary Evidence • Conclusions: • High degree of crystallinity or high temperature processing is not a compelling proof of radial mixing • High temperature processing of CAIs suggests radial outward transport in solar nebula, but reasoning requires broad body of evidence • Future modeling needs to evaluate different mechanisms (meridional flows, etc.) and must check for element fractionations Indicator: High temperature processing (crystallinity, refractory rich) NO (only possible if fast movement with micron dust) High temperature processing of chondrules: indicative of radial mixing? Good candidates High temperature processing of CAIs: indicative of radial mixing?

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