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Project Goals

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Planetesimal heating. 26Al as tool for radiometric dating: ... 26Al as planetesimal heat source: ... stronger heated planetesimals have earlier formed chondrule ... – PowerPoint PPT presentation

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Title: Project Goals


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 olivinepyroxene 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 olivinepyroxene 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 gt100
    (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)

lt900 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
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
Chemical complementarity of chondrules and matrix
in CV chondritesExemplified by Mg and Si (J.
Wood, P. Bland, H. Palme)
14
Chemical complementarity of chondrules and matrix
in CR chondritesExemplified 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
40
15
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
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)
Trapezium (Orion nebula)
  • ... injected into protoplanetary
  • disks (solar mass)
  • Radiometric dating
  • Planetesimal heating

18
26Al as tool for radiometric dating26Al-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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