Transcript here - The Planetary Chemistry Laboratory

Ay, for t’were absurd
To think that nature in the earth bred gold
Perfect i’ the instant: Something went before.
There must be remote matter.
Ben Jonson, The Alchemist, 1610
Stars and the Abundances of the Elements
Katharina Lodders, Washington University Saint Louis, USA
Why are we interested in the abundances
and the distribution of the elements?
It’s the stuff we are made of
Constitution of (baryonic) matter, numbers and amounts
of stable elements/isotopes
Composition and formation of the solar system, planetary
compositions; other solar systems
Origin of the elements in stars, element abundance
distributions are critical tests for nucleosynthesis models
Clues about the basic make-up and origins of matter
Aristotle's periodic table of the elements
Air
Fire
Earth
Water
The periodic table of the elements 2300 years later:
11 chemical elements known in antiquity
Fe, Cu, Ag, Au, Hg, C, Sn, Pb, As, Sb, S
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Cosmochemical Periodic Table of the Elements in the Solar System
2.43e10
2.343e9
H
He.
<3
abund. ...... Si = 1e6 atoms
EL ...... element symbol
Tc (K) ...... 50% condensation
temperature ...... refractory
box color:
at 1e-4 bar
common
lithophile
volatile
chalcophile
s=solid solution
highly volatile
siderophile
atmophile
55.47
0.7374
Li
Be
841.1
2.148e6
B
C
N
O
F
1142 s
1452 s
Ne
908 s
40
123
180
734 s
9.1
57510
1.020e6
Na
Mg
84100
1.000e6
8373
444900
5237
91200
Al
Si
P
S
Cl
958 s
1336
Ar
1653
1310
1229
664
948 s
47
3692
62870
34.20
2422
288.4
12860
9168
838000
2323
47800
527
K
Ca
Sc
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
1226
35.97
120.6
6.089
65.79
11.32
55.15
Zn
Ga
Ge
As
Se
Br
1006 s
1517
1659 s
1582
1429 s
1296 s
1158 s
1334
1352 s
1353 s
Kr
1037 s
699 s
980 s
887 s
1065 s
695 s
546 s
52
6.572
23.64
4.608
11.33
0.7554
2.601
1.900
0.3708
Rb
Sr
Y
Zr
Nb
Mo
Ru
Rh
1.435
0.4913
1.584
0.1810
3.733
0.3292
4.815
0.9975
5.391
Pd
Ag
Cd
In
Sn
Sb
Te
I
800 s
1464 s
1659 s
1741
1559 s
1590 s
1551 s
Xe
1392 s
1324 s
996 s
652 s
536 s
704 s
979 s
709 s
535 s
68
0.3671
4.351
0.4405
0.1699
0.02099
0.1277
0.05254
Cs
Ba
La
Hf
Ta
W
Re
0.6738
0.6448
1.357
0.1955
0.4128
0.1845
3.258
0.1388
Os
Ir
Pt
Au
Hg
Tl
Pb
799 s
1455 s
1578 s
1684 s
1573 s
1789 s
Bi
Po
At
Rn
1821 s
1812 s
1603 s
1408 s
1060 s
252 s
532 s
727 s
746 s
Fr
Ra
Ac
Rf
105
106
107
108
109
110
111
112
1.169
0.1737
0.8355
0.03572
Ce
Pr
Nd
K. Lodders, 2003,
1478 s 1582 s
Solar System Abundances
and Condensation Temperatures 0.03512
Th
Pa
of the Elements,
1659 s
Astrophys. J. 591, 1220-1247
Tc
Pm
1602 s
17.32
7.079e6 1.950e6 1.413e7
0.2542
0.09513
0.3321
0.05907
0.3862
0.08986
0.2554
0.0370
0.2484
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
1590 s
1356 s
1659 s
1659 s
1659 s
1659 s
1659 s
1659 s
1487 s
1659 s
Pu
Am
Cm
Bk
Cf
Es
Fm
Md
No.
Lr
9.31e-3
U
1610 s
Np
What is meant by abundance:
Solar abundances: present-day observable composition of Sun,
mainly photosphere; also sunspots, solar flares, solar wind
Solar system abundances: composition at birth of solar system
ISM/molecular cloud composition 4.6 billion years ago
proto-solar abundances
Li, D, short-lived radioactive nuclides: 26Al, 129I
long-lived (still present) radioactive nuclides: 87Rb, 235U, 238U, 232Th
Cosmic abundances: there is no “generic” cosmic composition
avoid use of “cosmic abundances”
many dwarfs stars are similar in composition as Sun,
but amount of elements heavier than He (=metallicity)
changes with time and varies across Milky Way Galaxy,
& other galaxies
Abundance is a relative quantity
Most commonly used abundance scales compare the number of atoms of an
element to a fixed (normalized) number of atoms of a reference element ,
(H or Si)
Astronomical abundance scale:
normalized to H, the most-abundant element in the universe
set to eH = 1012 atoms
gives the number of atoms of an element per one trillion H atoms
converted to log scale: A(H) = log eH = 12
abundances are measured relative to H, e.g.,
N(Fe)/N(H), so log eFe = log { N(Fe)/N(H) } + 12
used for H-rich systems: stars, ISM
Cosmochemical abundance scale:
normalized to Si, the most abundant cation in rock,
set to N(Si) = 106 atoms
gives the number of atoms of an element per one million Si atoms
used for planetary modeling, meteorites
1013
1012
1011
1010
109
US Natl debt = 6 T
Hydrogen 1 T
US deficit = 410B
InBev offer for AB = 52 B
NASA budget 2008/9 = 19 B
Shuttle launch (avg.) = 1.5 B
OEF+OIF/day = 410 M
Number
108
107
WU endowed gifts 2007
= 20 M
106
Millionaire = 1 M
Helium 96 B
Oxygen 580 M
Carbon 290 M
Silicon 41 M
Nickel 2 M
Chlorine 215 K
105
WU tuition 2008 = 36 K
10
Element Abundance
per 1012 H atoms
Fluorine 35 K
4
103
Gold/oz = 970
102
Oil/barrel = 140
101
Fed. min. wage/h = 5.85
100
10-1
10-2
One dollar
Parking meter = 0.25
One penny
Gallium 1480
Lead 130
Gold 8
Uranium 0.4
t ho u s a n d s | m i l l i o n s | b i l l i o n s | t r i l l i o n s
Amount US$
HUGE RANGE
IN VALUES
The atomic abundances
of the elements in the
solar system vary over
12 orders of magnitude
Where do the abundance numbers come from?
Earth’s crust
Meteorites
Solar photospheric spectrum
solar wind, solar energetic particles
Other solar system objects: gas-giant planets, comets, meteors
Spectra of other dwarf stars (B stars)
Interstellar medium
Planetary Nebulae (PN)
Galactic Cosmic Rays (GCR)
Also presolar grains found in meteorites
Elie de Beaumont, 1847:
~59 out of 83 stable & long-lived
elements are known
16 abundant elements
common to different crustal
rocks, ore veins, mineral &
ocean waters, meteorites, &
organic matter:
H, Na, K, Mg, Ca, Al, C, Si,
N, P, O, S, F, Cl, Mn, Fe
only later:
spectral analysis invented 1860s
Mendeleev’s periodic table 1869
There are 16 abundant elements common to
different crustal rocks, ore veins, mineral &
ocean waters, meteorites, & organic matter:
“This identity shows that the surface
of the Earth encloses in all its parts
everything that is essential for the
existence of organized beings...
... one sees that nature has provided
not only a settlement but also the
conservation of this indispensable
harmony.
The aging Earth will never cease to
furnish all the elements to the
organized beings necessary for their
existence”
Elie de Beaumont, 1847
Extend search for chemical
elements to other celestial
objects
I.A. Kleiber, 1885
68 elements are known &
periodic table is established
Compare:
Earth’s crust
Meteorites
Comets
Meteors
Sun
Other stars
Composition of celestial
objects is not random
Helium found in 1868 but not plotted,
no other noble gases known at the time
Sign Convention:
Elements
detected
in celestial
bodies
Elements
not detected
in celestial
bodies
-
Presence of
elements is
very uncertain
?
I.A. Kleiber's table
on the chemical
composition
of celestial bodies
1885
H
Zi
Be
B
C
N
O
F
Na
Mg
Al
Si
P
S
Cl
K
Ca
Sc ?
Ti
V
Cn
Mn
(Cu)
Zn
Ga ?
As
Se
Br
Rb
Sr
Yt
Zr
Nb ? Mo
(Ag)
Cd
In
Sn
Sb
Cs
Ba
La
Ce
Di -
Er (Au) - Hg
Tl -
Ta ?
Pb
Th -
Te
W-
Bi
U
Presence of
elements
is uncertain
Fe
Co
Ru ? Rh ?
Ni
Cu
Pt
Ag
I-
Os -
Ir -
Pt -
Au -
Abundances in the Earth’s crust & igneous rocks
Clarke 1898, Harkins 1917
Quantitative analyses
limited to abundant
Elements (wet.chem)
Notable exceptions:
light elements Li, Be, B (3-5)
are also quite rare
photo: K. Lodders
Light elements with atomic
numbers up to that of Fe (26)
are abundant, heavier
elements are rare
3-3.6 billion year old crust in Bangalore, India
Composition of the Earth’s crust
Clarke 1898, Harkins 1917
50
O
Crust: no discernable trends
of abundance with atomic
number or atomic weight
 Abundances were
modified from the initial solar
system element mixture
during Earth’s formation and
differentiation
Weight Percent
What controls the abundances
40
of the elements?
Check abundances
as a function of
30
atomic number or mass
Abundances in igneous rocks
(Table IX, col. II of Harkins 1917)
Si
20
10
Al
Na
0
C
6
F
K
Mg
P S Cl
Fe
Ca
Ti
Cr
Ni
8 10 12 14 16 18 20 22 24 26 28
Atomic Numbers
Earth’s crust abundances:
available material that can be analyzed in the lab
but not representative for composition of entire Earth
Earth materials are distributed between core, silicate mantle and crust
elements follow geochemical affinities:
metallic elements Fe, Ni, Co, Au, Ir,… move into the core
oxide and silicate rock-forming elements go
into silicate mantle and crust
Mg, Si, Al, Ca, Ti, REE…
Crust has elements with large ionic radii
that enter silicate melts and are incompatible in
silicate mantle minerals olivine, pyroxene
Si, Al, Ca, K, Na, REE, U, Th …
Earth is also not representative for solar system composition
Element fractionations started during formation of planetesimals from molecular
cloud material processed in the protoplanetary accretion disk (solar nebula) 
Before the solar system forms: stars feed gas and dust
to a molecular cloud:
Molecular cloud composition 4.6 billion years ago
gives the solar system composition
proto-Sun &
solar nebula
gas giant protoplanets
begin to form
evaporation &
recondensation
of dust
Meter to km size planetesimals begin to form mixtures of silicates, metal and
sulfides that may have been processed subsequently on their parent asteroids:
recondensed
silicate
metal
sulfide
chondrites
agglomeration
preserved
presolar
dust
accretion,
planetesimal
growth
primitive planetesimals
chondrite parent bodies
Planetesimals grow to larger asteroids and planets which
experienced melting:
achondrites &
iron meteorites
differentiated
planetesimals
break-up
terrestrial
planets
large
impacts
metallic core
formation during
heating
irons
achondrites
crust formation
basaltic volcanism
red
giants
super
novae
dust
Molecular cloud composition
4.6 billion years ago
= solar system composition
presolar molecular cloud
evaporation &
recondensation
of dust
proto-Sun &
solar nebula
Earth’s crust:
Good place to live,
bad place to
determine solar
system abundances
gas giant protoplanets
begin to form
recondensed
silicate
metal
sulfide
preserved
presolar
dust
agglomeration
accretion,
planetesimal
growth
primitive planetesimals
chondrite parent bodies
differentiated
planetesimals
break-up
terrestrial
planets
large
impacts
metallic core
formation during
heating
irons
achondrites
crust formation
basaltic volcanism
Earth’s
crust
today
Chondritic Meteorites
Chondrites: contain mineral phases that most closely resemble the original
solids that were present in the solar nebula –
TRY THESE FOR ABUNDANCES of non-volatile elements
Many types of chondrites contain round silicate spheres called chondrules
Chondrite groups: Ordinary chondrites: H, L, LL
Enstatite chondrites: EH, EL
Carbonaceous chondrites: CI, CM, CV, CO, CK, CR, CH
Bjurboele L/LL3 chondrite
Chondrules in the Tieschitz ordinary chondrite
Check meteoritic abundance distributions
Abundances vs. atomic number:
40
Harkins 1917
O
ABUNDANCE OF THE ELEMENTS
Use average abundances from
meteorites
no photospheric abundances yet
(stony meteorites; Harkins 1917)
30
Even-numbered elements are more
abundant than their odd-numbered
neighbors
Li, B, Be (3-5) are below scale,
C (6) low because of volatility, but
still more abundant than odd
numbered neighbors B (5) or N (7)
Weight Percent
Fe
20
Si
Mg
10
Abundances peak again at Fe (26)
S
0
Abundances of elements heavier
than Fe (26) are quite low
C
6
Na
Al P
Ca
K
Ni
Ti
Cr
Co
8 10 12 14 16 18 20 22 24 26 28
Atomic Numbers
Harkins’ discovery graph of the odd-even
effect in elemental abundances
Elemental abundances of CI chondrites match
those in the Sun
Photo: Le Muséum National d'Histoire Naturelle, Paris
(exceptions volatile elements H, C, N, O, noble gases)
Orgueil meteorite
“CI” stands for carbonaceous chondrite of Ivuna type
5 observed CI chondrite falls: Alais 1806 (6 kg), Ivuna 1938 (0.7 kg),
Orgueil 1864 (14 kg), Revelstoke 1965 (1 g), Tonk 1911 (10 g)
100
10
Sun holds more than 99% of
the solar system’s mass
0.1
0.01
0.001
Sun
Eris
Pluto
Neptune
Saturn
Mars
Ceres
0.00000001
Earth
0.0000001
Venus
0.000001
Jupiter
0.00001
Uranus
0.0001
Mercury
First done by
H.N Russell in 1929
1
mass%
Composition of Sun should
be good approximation for
solar system as a whole
mass distribution in the
solar system
Element determinations in the Sun
~66 elements out of 83 naturally occurring elements identified in
the photosphere
all stable elements up to atomic number 83 (Bi)
plus radioactive Th and U
~30 – 35 elements well determined in photosphere
Determined in photosphere with larger uncertainties:
> 0.10 dex: (factor 1.3)
Li, Be, B, N, Sc, Cr, Ni, Zn, Ga, Rh, Cd, In, Nd, Tb, Ho, Tm, Yb, Lu, Os, Pt
> 0.05 dex: (factor 1.12)
Mg, Al, Si, Ti, Fe, Co, Nb, Ru, Ba, Ce, Pr, Dy, Er, Hf, Pb
Difficult to determine (line blends, low abundance)
Ag, In, Sn, Sb, W, Au, Th, U; As, Se, Br, Te I, Cs, Ta, Re, Hg, Bi
He detected but difficult to quantify from spectra
He, Ne, Ar, Kr, Xe found in solar wind
Determined from Sun-spot spectra, relatively uncertain: F, Cl, Tl
Comparison of photospheric and CI chondritic
abundances (both scales normalized to Si=106 atoms:
1011
H
Good correlation for many
heavy elements (1:1 line)
Photosphere depleted in Li
Abundances of “missing”
rock-forming elements in
photosphere can be derived
from CI-chondrites
He.
109
108
abundant in sun,
volatile compounds
lost from meteorites
107
6
solar photosphere; Si = 10 atoms
Meteorites depleted in
elements that form
volatile compounds
Noble gases, CO,
CH4, N2, H2O
1010
Ne
106
N
S
105
Ar
Cr
ClMn
P
K
Ti
Co
FZn
Cu
V
103
101
Ge
Kr
Sc
Sr
Ga
RbZrB
Y
Ba
Pb
Sn
Mo
Ru
Cd
Pd
Ce
Os
Nd
Nb
Be
Ir
Dy
La
Rh
Gd
Li
Yb
Sm
Sb
TlEr
Hf
Pr
Eu
Ho
Tb
Lu
Xe
100
10-1
10-2
Mg
Si
Fe
Al
Ca
Na
Ni
104
102
O
C
1
1:
high in meteorites,
destroyed in sun
U
10-3
10-5 10-4 10-3 10-2 10-1 100 101 102 103 104 105 106 107 108
CI-chondrites; Si = 106 atoms
ilib
riu
m
ca lium
ox rbo bu
yg n b rn
en ur ing
sil
bu nin
ico
rn g
n
in
bu
g
rn
in
g
H
He.
109
Mg Si
Fe
Na
104
Ar
Al
P
103
Cl
Ca
K
Ti
Co
Zn
Cu
Ge
Sc
Ga
Se Kr
Sr
B
101
As
100
Br
Rb
Zr
Y
Mo Ru
Nb
Be
Sn Te
Pd Cd
Rh Ag
In
BB
X
10-1
le
Cr
Mn
V
Li
mainly neutron capture
on rapid and slow time scales
(R and S process)
Ni
F
102
ica
nu
c
S
105
ar
Ne
le
N
106
st
C
ist
O
107
at
108
qu
he
6
H
1010
10-2
Xe Ba
I
Sb
Pb
Pt
Ce Nd
OsIr
Hg
Dy
Cs La
SmGd
Er Yb
Au Tl Bi
Pr
Hf W
Eu
Ho
Tb
Re
Tm Lu
Ta
Th
U
0
10
20
30
40
50
atomic number, Z
60
70
80
90
Lodders 2003
solar system abundance by number, Si = 10 atoms
BB
bu
rn
in
g
The state of solar system elemental abundances as of 2003
1011
m
riu
He.
109
ilib
H
ca lium
ox rbo bu
yg n b rn
en ur ing
sil
bu nin
ico
rn g
n
in
bu
g
rn
in
g
H
1010
bu
rn
in
BB
Ne
Mg Si
Fe
Na
104
Ar
Al
P
103
Cl
Ca
Cr
Mn
K
Ti
V
Co
Zn
Cu
Ge
Li
Sc
Ga
Sr
As
Fe-peak
Be
Li,
Be, B most tightly
BBfragile
bound nuclei
X
100
10-1
10-2
peaks of elements
with tightly bound
nuclei
Xe Ba
Sn Te
Se Kr
B
101
mainly neutron capture
on rapid and slow time scales
(R and S process)
Ni
F
102
ica
nu
S
105
cle
ar
N
106
st
C
ist
O
107
at
108
le
qu
he
6
solar system abundance by number, Si = 10 atoms
1011
g
nuclear properties control abundances, not chemical (electron shell) properties
Br
Rb
Zr
Y
Mo Ru
Nb
Pd Cd
Rh Ag
In
I
Sb
Pb
Pt
Ce Nd
OsIr
Hg
Dy
Cs La
SmGd
Er Yb
Au Tl Bi
Pr
Hf W
Eu
Ho
Tb
Re
Tm Lu
Ta
Th
U
0
10
20
30
40
50
atomic number, Z
60
70
80
90
H, He (Li) produced in big-bang
Elements heavier than He produced in stars
Nucleosynthesis in the stellar core depends on a star’s initial mass:
Low-mass stars with masses less than ~8 times the Sun’s mass:
dwarf stars, Sun: main-sequence: H to He
for ~ 11 billion years
(Bethe, Weizaecker 1930s)
On the red giant branches:
He to C,O for ~110 million years
(AGB, carbon stars; Merrill 1952, Tc)
No more nucleosynthesis, white dwarfs
Light stars live long and produce mainly Helium, C and O, but also
Li, F, and several elements heavier than iron (e.g., Sr, Ba)
Nucleosynthesis models for red giant stars
have become testable through the
analysis of presolar grains found in
meteorites. These dust grains captured
the star’s nucleosynthesis products when
they formed in the stellar winds
H, He (Li) produced in big-bang
Elements heavier than He are produced in stars
Nucleosynthesis in the stellar core depends on a star’s initial mass:
Low-mass stars like the Sun (less than ~ 8 times the Sun’s mass)
dwarf star Sun, main-sequence:
H to He for ~ 11 billion years
On the red giant branches:
He to C for ~110 million years
No more nucleosynthesis, white dwarfs
Massive stars above ~ 8 times the Sun’s mass
e.g., 15 solar-mass star:
main sequence: H to He for ~ 8 million years
Red/blue supergiant stage:
He to C and O for
~1.2 million years
C to Ne and Mg for ~1 thousand years
O and Ne to Si and S ~0.6-1.3 years
Si and S to Fe, Ni
~12 days
Supernova: few seconds
B2FH 1957, Cameron 1957
Light stars live longer and produce mainly Helium, C and O
Massive stars have short lives and produce essentially all the abundant
elements up to Fe
“Shells” containing the
principal products of the
nucleosynthesis stages in
massive stars are detected in
SN remnants through X ray
emissions
Cas-A
Broadband, Si, Ca, Fe
Chandra X-ray observatory
The elements heavier than iron: e.g., Sr, Ba, Au, Pb, U
Production of elements heavier than iron requires input of energy, no more
fusion reactions of lighter elements
The heavy elements are built-up by neutron capture on pre-existing nuclides
such as iron
2 different possibilities:
Slow neutron capture during alternate H shell and He-shell burning
in red giant stars
“slow” compared to the beta-decay rates of the interim produced radioactive
nuclides. These decay to a stable atom before another neutron is captured
Rapid neutron capture during supernova explosions
“rapid” compared to the beta decay rates of the interim produced radioactive
nuclides
Different isotopes of the heavy elements are preferentially made by either the
S or R process
 contribution of SN and giant stars to solar system element mixture
Sr
fraction of total element
1.0
Ba
Au Pb
AsSeBr Kr Rb Sr Y Zr NbMoTcRuRhPdAgCd In SnSbTe I XeCsBaLaCe Pr NdPmSmEuGdTbDyHo ErTmYb Lu Hf Ta W ReOs Ir Pt AuHg Tl Pb Bi
U, Th
Th
U
0.8
0.6
0.4
0.2
0.0
40
50
Legend:
60
atomic number, Z
main S
Low-intermediate
giant stars
weak S
70
80
90
P process R process
---------Massive stars ------
Where the heavy elements in our solar system come from
Supernovae produce most of the abundant
elements heavier than He: C, N, O, Mg, Si, Fe, …
R – rated = R process…
SN also contribute to elements
heavier than iron
Composition of the
Human Body
(mass %)
carbon
20.5%
hydrogen
10%
nitrogen 2.8%
calcium 1.5%
phosphorus
K, S, Na, Cl
other elements
< 0.06%
oxygen 63.4%
H from big bang, maybe up to half of all C and N from giant stars,
all other major elements made in massive stars going supernova…
For more information and reprints of our work
please visit the Planetary Chemistry laboratory’s webpage at:
http://solarsystem.wustl.edu
for solar abundances see:
Lodders 2003, Astrophysical Journal 591(2) 1220-1247, Solar system
abundances and condensation temperatures of the elements.
for a compilation of various physical and chemical data on solar
system objects see:
Lodders, K. & Fegley, B. 1998, The Planetary Scientist's Companion,
Oxford Univ. Press, pp. 384
for a less technical description see
Lodders, K. & Fegley, B., 2008/2009, Chemistry of the Solar System,
Royal Society of Chemistry, coming soon to a bookstore near you