www.sciencemag.org/cgi/content/full/332/6037/1528/DC1

Supporting Online Material for

The Oxygen Isotopic Composition of the Sun Inferred from Captured Solar Wind

K. D. McKeegan,* A. P. A. Kallio, V. S. Heber, G. Jarzebinski, P. H. Mao, C. D. Coath,

T. Kunihiro, R. C. Wiens, J. E. Nordholt, R. W. Moses Jr., D. B. Reisenfeld, A. J. G. Jurewicz, D. S. Burnett

*To whom correspondence should be addressed. E-mail: mckeegan@ess.ucla.edu

Published 24 June 2011, Science 332, 1528 (2011)

DOI: 10.1126/science.1204636

This PDF file includes:

Materials and Methods Figs. S1 to S6 Tables S1 and S2 References and Notes

1

Supplement

Sample collection

The Genesis spacecraft exposed the Concentrator instrument to the solar wind (SW)

while at the Earth-Sun libration point to avoid contamination by magnetospheric material

surrounding the Earth. The instrument was pointed 4.5±1 ahead of the Sun, which is the mean

direction of the SW after accounting for the spacecraft forward velocity. The Concentrator

focused ions over 803.28 days between day 339 of 2001 and day 93 of 2004. Brief interruptions

occurred for instrument safings, for off-Sun maneuvers, and during times of very high-speed

streams > 800 km/s, above which the instrument was not designed to operate. Overall, the

instrument collected SW for all but 44 days from the start of the Genesis mission science phase

until its conclusion. The proton rejection grid encountered a problem during turn-on and could

not be operated at its full potential. This limitation increased the flow of hydrogen to the target

by a factor of ~2.5, to a maximum of ~1.5 x 1017

protons/cm2 near the center of the target

assembly, with all of the additional protons coming during high speed flows. The additional

proton radiation does not appear to have any effect on the implanted oxygen or on the analysis

thereof.

The Genesis collection period occurred just after solar maximum, during which time the

mean velocity was significantly higher than that averaged over a typical eleven-year cycle. The

higher mean velocity resulted in a slightly lower concentration factor than predicted (58). In

addition, the angular distribution of the incoming ions was narrower than predicted, mostly due

to better than expected pointing of the spacecraft and instrument. This resulted in a significantly

steeper instrumental fractionation trend from the center of the target to its edge. This trend is

fully characterized by precise neon isotopic analyses (17).

Sample selection and preparation

Due to the shallow implantation depth of the SW (peak ~80 nm), minimal surface

preparation was employed. SiC target #60001 was ultrasonicated in xylene in a clean room

facility at the Jet Propulsion Laboratory and blown dry with a nitrogen gas jet and placed in a

custom-designed MegaSIMS sample holder. The sample was then transferred to UCLA in a

clean container and then put into the vacuum system of the MegaSIMS where it remained for 2

years (total time exposed to atmosphere in the MegaSIMS lab was < 5 minutes). The sample

was in the MegaSIMS vacuum storage vessel (SAS) for most of the time, in vacuum ranging

from 1.5×10-10

to 5×10-10

Torr. During weekends, sample 60001 was typically placed inside the

sample chamber for baking, with He-cryo pump operating continuously. Normal pressure in the

sample chamber is so low that it is unreadable by our ionization gauge (limit ~5×10-11

Torr), but

is estimated to have been <2×10-11

Torr. During baking the pressure would typically rise into the

~10-9

Torr range.

Sample areas analyzed were first selected optically to be free from defects or particles

larger than a few micrometers and were then cleaned just prior to analysis by in situ sputtering

with a low-energy (5 keV impact) Cs beam rastered over 300×300 μm2

centered on the targeted

area. Low-energy sputtering for 500 seconds at 10 nA removed the top ~20 nm of the sample

with an e-folding length scale of ~ 1 nm, resulting in minimal mixing of surficial adsorbed

terrestrial oxygen with the implanted SW (14).

2

Effectiveness of surface cleaning

16

O implants into SiC as well as a blank SiC target (made during the same time period as

sample 60001 but not exposed to solar wind) were analyzed to verify the effectiveness of the 5

keV impact energy Cs+ sputtering for the removal of adsorbed surface oxygen. Depth profiles

were collected with and without sputter cleaning under otherwise similar conditions of 20 keV

impact energy Cs+ sputtering with 20 nA and a nominal raster size of 130×130 µm2. The profiles

are shown in Figure S1. When the cleaning is applied to blank SiC, asymptotic (linear)

background levels are reached almost instantly meaning that after 20 nm cleaning there is

negligible contribution from the exponential surface contamination to the implanted oxygen

profiles.

Figure S1. Effectiveness of 5 keV Cs+ sputtering in removing surface oxygen contamination.

Depth profiles of 16

O2+

from an artificial implant and a blank SiC wafer. The lack of signal at the

start of the profiles with cleaning indicates the time when 16

O- imaging was used to look for

contaminant particles inside the optical gate. At the beginning of the profile without cleaning, 16

O- was blocked off with a slit in the recombinator mass focal plane to protect the electron

multiplier from excessively high counts. The depth of the artificial implant was greater than the

peak of the Genesis SW implant (dashed line), so surface contamination would be even worse for

Genesis, if not for the low-energy cleaning procedure.

Procedure for data acquisition

Following sputter-cleaning, the ion extraction voltage and primary beam focusing were

switched to the analytical mode (20 keV impact energy, 20 nA Cs+ rastered over 130×130 μm

2)

and the ion microscope imaging capability of the MegaSIMS was used to rapidly inspect the

analytical area for contaminant dust particles larger than a few hundred nanometers. If any were

identified (the usual case), the sample was shifted slightly such that the offending dust was

outside the analytical area of the depth profile as defined by an optical gate (“field aperture”)

inserted into an image plane of the secondary ion beam path. Oxygen on the immersion lens

extraction plate was "cleaned" (more accurately, buried) by sputtering a blank SiC sample with

undetectable O concentrations with a 100-150 nA Cs+ primary beam and 150×150 μm

2 raster,

3

lasting either all night or ~2 hours in the morning immediately preceding a sample analysis.

Negative secondary ions produced by Cs sputtering were accelerated to 10 keV and mass

filtered with an „isotope recombinator‟ (14) such that only masses 16-17-18 were injected into

the tandem accelerator with its high-energy terminal held at +1.2 MV. Collisions (electronic

energy loss) with dilute Ar gas at pressure 10.5 Torr stripped electrons from the incoming

beam, resulting in the destruction of molecular ions and a second acceleration of the now

positively charged beam back to ground potential. The +2 charge state (3.6 MeV) was selected

via an energy analyzer since prior measurements of terrestrial minerals found no detectable

molecular ion interferences (e.g., hydrides) in the +2 mass spectrum (14). Tests on standard

materials demonstrated a total transmission of > 46% through the accelerator under these

conditions, which is approximately 3 times better than the transmission that can be achieved in

conventional (low energy) SIMS utilizing high mass resolving power to discriminate hydride

interferences.

The in-depth distributions of implanted SW oxygen ions were determined by magnetic

filter separation and simultaneous detection of the three O2+

isotope beams by ion counting.

Integration times were 1 second for the first minute and then 5 seconds thereafter. Sputtering

continued through the implanted solar wind layer (mean depth ~ 80 nm) until a steady-state

background due to residual oxygen from the MegaSIMS vacuum was reached (typically at

depths > 300 nm). Background-corrected solar wind depth-profiles are well-fit by a Gaussian

(normal) distribution reflecting the SW velocity dispersion and multiple impact angles onto the

Concentrator target. Measured ion count rates were corrected for detector deadtime and duty

cycle.

The intrinsic deadtime of our ETP electron multipliers and ion counting system is ~30 ns.

The effective deadtime is higher in a case of an optically gated-raster because the multiplier

actually sees alternating pulses of intense count rates and periods of inactivity depending on

whether the secondary beam is inside or outside the field aperture. The measured counts

represent averages over the integration cycles. The ratio of the gated secondary beam (rastered

primary beam) to the full secondary beam intensity (unrastered primary beam) is called the duty

cycle, and gives a coefficient by which to calculate effective deadtime (the duty cycle for a

defocused beam or a focused unrastered beam is unity since in this case the average count rate

equals the instantaneous count rate). In the MegaSIMS, the measured duty cycle from analysis

of magnetite is ~1/3, with the same analytical setup as in the measurement of SW. This

corresponds to the ratio of the sample image that is passed through the field aperture (100 μm

diameter) to the area of pit size (150×190 μm2). Thus the effective deadtime used for the

correction of magnetite and SW analyses was 90 ns. The maximum intensity at the peak of the

SW profile is ~105 cps for

16O

2+, corresponding to a maximum deadtime correction of ~10‰.

The accuracy of the deadtime correction is a fraction of this value, thus the deadtime effect

cannot cause a systematic error in the 16

O abundance determination under our measurement

conditions beyond ~3‰.

Radial distances of analytical pits

Forty depth profiles were measured in a traverse of the SiC target from area A to E (Fig.1

and Fig. S2). The positions of analysis pits were measured using the motor drive coordinates of

the MegaSIMS sample stage. These stage coordinates were converted into Concentrator-centric

coordinates by referencing the radial edges of the quadrant to their position in the Concentrator

target assembly (by adding 0.457mm to x and y and computing the hypotenuse). The radial

4

distances for each pit were used for the concentrator mass-fractionation correction applied to

each analysis, based on the neon isotopic fractionation curve as a function of concentrator radius.

Pit Depths, cleaning depths and sputter rates

Time-to-depth conversion was calibrated following completion of all analyses via

measurements of final pit depths with an optical interferometer by assuming a constant sputter

rate (Fig. 1). This total depth includes low-energy cleaning and sputtering for analysis. The

erosion depth due to cleaning was estimated every day using a 16

O, 18

O implant (LANL2007-2,

made at Los Alamos National Lab) by collecting consecutive depth profiles with and without

low-energy cleaning. This information was used to decide the sputtering time for cleaning (500

s), and applied to sample 60001 analyses. After subtracting the cleaning depth from the total pit

depth, the average sputter rate during analysis could be calculated for each depth profile from the

remaining pit depth and time of analysis.

Figure S2. Composite reflected light micrograph of a radial section of Genesis SiC target 60001

from inner region (area A) to periphery (area E).

Concentration factor as a function of radial position

In agreement with the Ne data reported by Heber et al. (17), the concentration of SW ions

falls systematically by a factor of ~5 from the interior to the peripheral regions of the target (Fig.

S3).

Standards and calibration of instrumental mass fractionation

Mass-dependent fractionation during measurement in the MegaSIMS was determined by

analyses of terrestrial standard materials of known oxygen isotopic composition made under

identical instrumental conditions (with the exception of primary beam current). One problem is

that materials that are frequently used as oxygen isotope standards in SIMS are electrical

insulators and require the use of an electron gun for charge compensation. In the case of Genesis

solar wind measurements, the abundance of solar wind oxygen is so low that the use of the

electron gun is not practical because it increases the oxygen background (due to heating in the

transfer optics section of the instrument). A magnetite (59) of known composition (Centre

Afrique, =+1.42 ‰) was chosen as our primary terrestrial calibration standard because, like

5

SiC, it is sufficiently conducting that no charge compensation by extra electrons is required for

analysis with a Cs+ beam. Tests against other terrestrial standard materials (NIST glass, San

Carlos olivine, Burma spinel, and quartz), this time utilizing the normal incidence electron gun,

confirmed that all lie on a single mass-dependent fractionation line as they must. However, the

choice of magnetite as the primary standard potentially introduces a "matrix effect" on the

instrumental mass bias, i.e., the mass-dependent (isotopic) fractionation inherent in SIMS can

depend on the Chem. composition of the sample. The magnitude of the matrix effect relative to

olivine is ~ 3-4 ‰ /amu favoring the light isotopes. Because (a) the matrix effect is strictly

mass-dependent, (b) this magnitude is within the envelope of other uncertainties in correcting

mass-dependent fractionation, including those due to Concentrator induced fractionation and SW

acceleration, and (c) there is no existing SiC standard upon which to base a second-order

correction, we don't correct for possible matrix effects at this time.

Figure S3. Left: Composite reflected light image of sample 60001. The approximate locations

of each analyzed area are shown by the colored boxes (cf., Fig. S2). Right: Corresponding 16

O2+

intensity vs. time in 40 depth profiles from radial traverse of sample 60001; colors are coded

according to the position along the traverse. Slight deviation in peak centers and intensity in a

given analytical area is due to slightly different primary beam intensities. Sputter rate was

calibrated for each profile by measurement of crater depth following completion of all analyses.

Eagle Station olivine

A special effort was made to test the accuracy of 17

O determinations with MegaSIMS

given the importance of this parameter (as opposed, for example, to the uncertainties inherent in

the mass-dependent fractionation of the SW). The electron gun was used for charge

compensation for these tests because the standard materials investigated include insulators:

6

olivine from Earth's mantle (San Carlos, Arizona, USA) and from the Eagle Station pallasite.

Data were first collected with three electron multipliers using a ~50 pA unrastered Cs+ primary

beam, and a pre-sputter of 120s with a 1 nA 20×20 m2 rastered beam (Fig. S4-A). A second

session was measured with more intense secondary beams by collecting 16

O2+

into a Faraday cup

and using electron multipliers for the minor isotopes (Fig. S4-B). The primary beam in this case

was 0.8 nA with a 20×20 m2 raster and a 4-5 min pre-sputter using the same beam. The result

obtained with three multipliers is ‰, whereas introducing one Faraday cup

yielded 0.8 ‰. The accepted value for Eagle Station pallasite is

‰

(60). The test demonstrates accuracy of at the order of ~1‰, given sufficiently precise

counting statistics. The data plotted in Fig. S4 are normalized for instrumental mass

fractionation by using San Carlos olivine. Thus the matrix effect between olivine and magnetite

(Centre Afrique standard) is apparent as the magnetite data in Fig. S4 display too low and

values. Note, however, that

= 0 since this is independent of mass-fractionation

correction. In principle, the Eagle Station data should be corrected for a matrix effect due to its

higher fayalite (FeO) content compared to San Carlos olivine. Such effects have been reported

previously (61) and can shift the data in a mass-dependent sense by ~0.5‰/amu for each 10%

change in fayalite content, depending on measurement conditions in the ion probe. This matrix

effect would shift of Eagle Station by only ~1‰ and would have no effect on

thus we

neglect it here.

Figure S4. Oxygen isotope measurements of Eagle Station olivine relative to terrestrial standard

materials made using three electron multipliers (A) and a Faraday cup with two multipliers (B).

Error bars are 1sigma and ellipses are 95% confidence of the mean (black squares=San Carlos

Olivine; blue diamonds = Central Afrique magnetite; green triangles=Eagle Station olivine; open

diamond = bulk Eagle Station pallasite from (60)). Terrestrial fractionation line (TF) and CAI-

line are shown for reference.

A B

7

Data reduction procedures

Raw counts of magnetite data were corrected for deadtime as discussed above and cycles

with transient spikes in count rate (due to accelerator instability) were removed in general < 10

out of 400 cycles (10 rejection criterion on running mean of cycle-by-cycle ratios). The

magnetite data were used to compute the mean 18 (≡ (18

O/16

O)measured / (18

O/16

O)true ) and 17 for

each analytical session. The standard deviation of multiple magnetite profiles was propagated

into the uncertainty estimate for the SW profiles by adding in quadrature to the Poisson statistics

for a given profile.

Data for the SW profiles were corrected for deadtime, spikes, background and

instrumental mass fractionation. The background correction was based on the mean values

obtained for each isotope over the deep tail of a profile, typically the last 20 to 30% of the crater

depth. To compute isotope ratios, the profile of each isotope was fit by a Gaussian from -1 to

+1.5 relative to the peak center (initially guessed, then iterated) in order to consistently define

the integration limits. Note, due to constant SW speed the energy of the implanted SW isotopes

is slightly different based on their different masses and thus the depth distribution of each isotope

in the target. The integral over the measured profile from -1 to +6 was then computed for

each isotope. Corrections for any residual terrestrial oxygen that was not removed from the

sample surface are thought to be minor and were not made. Despite our best efforts, due to the

low concentration of SW at radial distances ≥ 20 mm from the target center, the oxygen isotope

data from the areas D and E appear to be slightly contaminated by terrestrial oxygen as indicated

by marginally higher values (see Fig 2). Therefore, these areas were not included in the

final determination of the bulk SW oxygen isotope composition. Data for all profiles are

summarized in Figure S5 and Tables S1, S2.

Correction of the Concentrator induced mass fractionation using Ne. The solar wind implanted Ne was measured with high spatial resolution in the

Concentrator target (Fig. S6) in order to determine the mass-dependent fractionation induced by

the Concentrator as a function of radial position on the target. This is directly calculable by

comparing these data with the Ne isotopic composition in the bulk solar wind in a passive

collector (17). The Ne data also demonstrated that the fractionation in the Concentrator is mass-

dependent (17). Heber et al. (17) further argue, based on the similarity of charge-to-mass ratios

and extensive instrument modeling studies (13, 62), that the fractionation factor based on the 22

Ne/20

Ne ratios at a given radial distance is directly applicable for correcting the measured

oxygen isotopic compositions. The Ne data provide a curve that allows one to read off the

appropriate isotopic mass fractionation at each radial position (Fig. S6). For instance, at a

distance of 5.5 mm from the center of the concentrator target (area A), the deviation of the

measured Ne relative to the bulk SW Ne is +40‰. The measured 18

O at this position is ~-65‰.

Knowing that the heavy isotope 18

O is enriched by 40‰ relative to 16

O, we correct the measured

18

O thus: -65‰-(40‰) = -105‰. This correction was applied individually to each

measurement. Fig. S6 shows that correcting the 4 inner areas results in identical average 18

O

values. The uncertainty of this correction of 1.25‰ per mass unit as indicated by the 95%

confidence limit of the 20

Ne/22

Ne data fit (2) is not included in the error estimates for the final

solar wind composition.

8

Fig. S5. Measured isotopic

compositions of all 40 SW

profiles, corrected for

instrumental mass

fractionation and normalized

to SMOW. All but 2 profiles

plot in the 16

O-enriched

region (below the TF line),

and one profile (labeled) was

visibly contaminated by a

terrestrial dust particle.

Uncertainty estimates There exist several types of uncertainty in the experiment and its interpretation and these

must be considered independently for their effects on mass-dependent and mass-independent

measures of the isotope composition of the SW (and of the Sun). Measurement uncertainties on

isotope ratios in depth profiles are the most straightforward and are addressed in various sections

of this SOM document. For example, errors quoted on single profile data are based on 1

Poisson statistics combined with the instrumental mass fractionation correction determined from

the standards. The latter ignores possible matrix effects, which however are strictly mass-

dependent (see above discussion on standards). Mass-independent errors (17

O shifts) can arise

because of terrestrial contamination (which can only move data toward the TF line) and deadtime

effects. Careful evaluation of the latter shows a limit of possible systematic errors of ±3‰ in

17

O. The errors quoted for the SW 17

O composition are based on a weighted mean over all

profiles in the areas A, B, F, and C. The 18

O and 17

O errors are 1 standard deviation of the

group averages after correction for Concentrator induced mass-dependent fractionation. The

uncertainty in the Ne-based correction is about 1.25‰/amu, not accounting for any systematic

uncertainty in the different behaviors of Ne and O in the Concentrator ion optics. This error is

strictly mass-dependent and, as discussed above, is minor. Finally, we do not quote uncertainty

on the inferred solar composition because it is an hypothesis. The only parameter which is well-

constrained is 17

O of the Sun; all other systematic uncertainties are mass-dependent and

significantly smaller than the hypothesized isotopic mass fractionation in the acceleration of the

solar wind.

9

Fig. S6. Upper panel:

22Ne relative to the bulk solar wind as function of the distance from the

concentrator target center (cf. 3). The deviation of the Ne isotopic composition in the

concentrator target relative to the bulk SW reflects the concentrator-induced isotopic

fractionation. Lower panel: Measured 18

O and value after correction for concentrator-induced

fractionation. The final isotopic composition of oxygen in the bulk solar wind is represented by

the dashed line, which is the mean value of the data of the areas A, B, F, and C. Note, data from

D and E had to be discarded (see Data reduction procedures). Error bars of the measured

oxygen data are as in Table S2.

10

Table S1. Single measured and corrected oxygen isotopic composition data of solar wind implanted into

the Genesis Concentrator quadrant 60001

Analysis number

Concentrator radius (mm)

16O

2+ at

peak (cps)

18O

(‰) 1 err

17

O (‰)

1 err Δ

17O

(‰) 1 err

Ne fractiona-tion factor per amu

18

O (‰, Ne

corrected)

17

O (‰, Ne

corrected)

A-01 5.98 1.08E+05 -65.1 3.6 -55.7 8.0 -21.9 8.3 1.0197 -104.5 -75.4

A-02 5.59 1.10E+05 -74.4 3.6 -73.8 8.0 -35.1 8.2 1.0201 -114.7 -93.9

A-03 5.52 1.11E+05 -65.0 3.6 -70.7 8.0 -36.9 8.2 1.0202 -105.3 -90.9

A-04 5.45 1.09E+05 -62.4 3.6 -61.9 8.0 -29.4 8.2 1.0203 -102.9 -82.1

A-05 5.93 1.14E+05 -56.9 3.6 -66.7 8.0 -37.2 8.2 1.0198 -96.4 -86.5

B08-01 9.29 1.14E+05 -62.4 6.2 -62.2 8.5 -29.8 9.1 1.0158 -93.9 -78.0

B08-02 9.53 1.12E+05 -61.6 6.2 -38.0 8.6 -6.0 9.2 1.0154 -92.4 -53.5

B08-03 9.70 1.09E+05 -68.6 6.2 -54.9 8.6 -19.3 9.2 1.0152 -98.9 -70.1

B08-04 9.21 1.16E+05 -62.1 6.2 -57.0 8.5 -24.6 9.1 1.0159 -93.9 -72.8

B08-05 9.38 1.09E+05 -66.4 6.2 -77.2 8.5 -42.7 9.1 1.0156 -97.6 -92.9

B08-06 9.60 1.05E+05 -67.5 6.2 -59.5 8.7 -24.4 9.3 1.0153 -98.2 -74.8

B08-07 9.85 1.11E+05 -66.3 6.2 -71.2 8.4 -36.7 9.0 1.0149 -96.2 -86.2

B08-09 9.36 1.14E+05 -63.7 6.2 -54.8 8.6 -21.7 9.2 1.0157 -95.0 -70.5

B-01 10.03 9.56E+04 -68.0 3.8 -54.2 8.5 -18.9 8.8 1.0147 -97.3 -68.9

B-02 10.01 9.77E+04 -76.3 3.8 -62.4 8.5 -22.7 8.7 1.0147 -105.8 -77.1

B-03 9.70 9.96E+04 -61.6 3.8 -58.0 8.5 -26.0 8.7 1.0152 -91.9 -73.2

B-04 9.49 1.00E+05 -71.5 3.8 -71.1 8.4 -33.9 8.6 1.0155 -102.4 -86.6

C-01 15.52 6.58E+04 -93.9 4.4 -88.3 9.7 -39.5 10.0 1.0055 -104.9 -93.8

C-02 15.72 6.11E+04 -101.2 4.4 -76.2 9.9 -23.5 10.2 1.0051 -111.5 -81.3

C-03 15.94 6.45E+04 -80.9 4.5 -65.1 10.1 -23.0 10.3 1.0048 -90.5 -69.9

C-04 15.74 6.66E+04 -97.9 4.4 -75.5 10.0 -24.6 10.2 1.0051 -108.1 -80.6

C-05 15.74 6.63E+04 -92.7 4.4 -91.7 9.9 -43.5 10.1 1.0051 -102.9 -96.8

D08-08 20.23 7.06E+04 -92.1 7.0 -44.3 11.9 3.6 12.5 0.9982 -88.4 -42.5

D-01 20.90 3.93E+04 -99.1 5.5 -72.3 12.5 -20.8 12.8 0.99730 -93.7 -69.6

D-02 20.62 4.11E+04 -100.6 5.4 -72.8 12.3 -20.5 12.6 0.99766 -96.0 -70.5

D-03 20.83 3.95E+04 -101.5 5.5 -52.4 12.6 0.4 12.9 0.99740 -96.3 -49.8

D-04 20.75 3.96E+04 -92.8 5.5 -76.8 12.4 -28.5 12.8 0.99749 -87.8 -74.3

D-05 19.65 4.57E+04 -86.1 5.2 -80.1 11.7 -35.3 12.0 0.99894 -84.0 -79.0

D-06 20.62 4.07E+04 -91.2 5.5 -70.2 12.4 -22.8 12.7 0.99765 -86.5 -67.9

E-01 24.81 2.49E+04 -82.3 6.8 -65.4 15.5 -22.6 15.9 0.99345 -69.2 -58.9

E-02 25.30 2.34E+04 -70.8 7.0 -49.1 16.0 -12.2 16.4 0.99309 -57.0 -42.2

E-03 24.93 2.45E+04 -100.9 6.8 -82.2 15.4 -29.8 15.8 0.99336 -87.6 -75.6

E-04 24.62 2.58E+04 -102.6 6.6 -82.0 15.1 -28.6 15.5 0.99359 -89.8 -75.6

E-05 24.28 2.64E+04 -97.3 6.5 -62.5 15.0 -11.9 15.4 0.99387 -85.0 -56.4

E-06 24.72 2.55E+04 -87.0 6.7 -57.7 15.4 -12.5 15.8 0.99352 -74.0 -51.2

E-07 25.04 2.43E+04 -71.7 6.9 -83.5 15.5 -46.2 15.9 0.99327 -58.3 -76.7

F-01 12.77 8.54E+04 -84.1 4.0 -71.2 9.0 -27.5 9.2 1.0103 -104.6 -81.5

F-02 13.05 8.41E+04 -81.6 4.1 -71.1 9.1 -28.7 9.4 1.0098 -101.2 -80.9

F-03 13.02 8.04E+04 -80.2 4.1 -58.9 9.2 -17.2 9.4 1.0098 -99.9 -68.8

F-04 13.04 8.27E+04 -88.5 4.0 -62.0 9.1 -16.0 9.4 1.0098 -108.0 -71.8

Errors on single profile data are based on 1 Poisson statistic and the uncertainty in the instrumental mass fractionation correction.

11

Data of B08-02 (italics) were rejected due to contaminant particle in analyzed area. The particle was recognized in the ion image and later confirmed via microscopy. See text for the calculation of Ne isotopic fractionation factors and correction of the oxygen isotopic composition.

Table S2. Group averages of the measured and corrected SW oxygen isotopic composition, and the final

solar wind and solar oxygen isotopic composition

Group means: Measured data Corrected for Concentrator mass

fractionation

Group Mean radius (mm)

18

O (‰)

1 err

17O

(‰) 1 err

Δ17

O (‰)

1 err

18O

(‰) 1 err

17

O (‰)

1 err

area_A 5.7 -64.8 6.4 -65.8 7.2 -32.1 6.5 -104.8 6.5 -85.8 7.3

area_B 9.6 -66.8 4.4 -62.1 7.8 -27.3 7.6 -97.4 4.0 -77.4 7.9

area_C 15.7 -93.3 7.7 -79.4 10.7 -30.8 9.9 -103.6 8.0 -84.5 10.9

area_D 20.5 -94.8 5.7 -67.0 13.3 -17.7 14.4 -90.4 4.9 -64.8 13.4

area_E 24.8 -87.5 13.3 -68.9 13.7 -23.4 12.7 -74.4 13.6 -62.4 13.8

area_F 13.0 -83.6 3.6 -65.8 6.3 -22.4 6.7 -103.4 3.7 -75.8 6.4

mean SW oxygen composition, corrected

-102.3 3.3 -80.8 5.0

solar oxygen composition, deduced

-58.5

-59.1

Errors of the average values are 1 standard deviation. Error of the final solar wind composition (average of A, B, C, and F) is 1 standard deviation of the corrected group averages. For deduction of the solar oxygen isotopic composition see text.

12

References and Notes 1. R. N. Clayton, L. Grossman, T. K. Mayeda, A component of primitive nuclear composition in

carbonaceous meteorites. Science 182, 485 (1973).

2. K. D. McKeegan, L. A. Leshin, S. S. Russell, G. J. MacPherson, Oxygen isotopic abundances in calcium-aluminum-rich inclusions from ordinary chondrites: Implications for nebular heterogeneity. Science 280, 414 (1998).

3. N. Sakamoto et al., Remnants of the early solar system water enriched in heavy oxygen isotopes. Science 317, 231 (2007).

4. A. J. Fahey, J. N. Goswami, K. D. McKeegan, E. K. Zinner, 16O excesses in Murchison and Murray hibonites - A case against a late supernova injection origin of isotopic anomalies in O, Mg, Ca, and Ti. Astrophys. J. 323, L91 (1987).

5. L. R. Nittler et al., Aluminum‐, calcium‐ and titanium‐rich oxide stardust in ordinary chondrite meteorites. Astrophys. J. 682, 1450 (2008).

6. R. N. Clayton, Solar system: Self-shielding in the solar nebula. Nature 415, 860 (2002).

7. J. R. Lyons, E. D. Young, CO self-shielding as the origin of oxygen isotope anomalies in the early solar nebula. Nature 435, 317 (2005).

8. R. A. Marcus, Mass-independent isotope effect in the earliest processed solids in the solar system: A possible chemical mechanism. J. Chem. Phys. 121, 8201 (2004).

9. M. H. Thiemens, Mass-independent isotope effects in planetary atmospheres and the early solar system. Science 283, 341 (1999).

10. H. Yurimoto, K. Kuramoto, Molecular cloud origin for the oxygen isotope heterogeneity in the solar system. Science 305, 1763 (2004).

11. M. Asplund, N. Grevesse, A. J. Sauval, P. Scott, The chemical composition of the Sun. Annu. Rev. Astron. Astrophys. 47, 481 (2009).

12. D. S. Burnett et al., The Genesis discovery mission: Return of solar matter to Earth. Space Sci. Rev. 105, 509 (2003).

13. R. C. Wiens et al., Genesis solar wind Concentrator: Computer simulations of performance under solar wind conditions. Space Sci. Rev. 105, 601 (2003).

14. P. H. Mao, D. S. Burnett, C. D. Coath, G. Jarzebinski, K. D. McKeegan, MegaSIMS: a SIMS/AMS hybrid for measurement of the Sun’s oxygen isotopic composition. Appl. Surf. Sci. 255, 1461 (2008).

15. At any one time, the SW is a constant-velocity plasma; thus, isotopes vary in kinetic energy. The difference in implantation depth in the Concentrator target is ~1.5 nm per mass unit at the peak of the profile.

16. The −6.5-kV potential of the interior of the Concentrator resulted in higher implantation energies in the range of 46 to 100 keV for oxygen’s dominant charge states of +6 and +7 and incident velocities of 300 to 800 km/s. Typical incident angles at the target are 10° to 55° from normal for the main portion of the target, resulting in depth profiles with peaks near 80 nm.

13

17. V. S. Heber et al., Isotopic and elemental fractionation of solar wind implanted in the Genesis concentrator target characterized and quantified by noble gases. Meteorit. Planet. Sci. 46, 493 (2011).

18. One profile from area B was removed from the average because it is known to be partially contaminated by a dust particle (SOM).

19. R. N. Clayton, Oxygen isotopes in meteorites. Annu. Rev. Earth Planet. Sci. 21, 115 (1993).

20. P. Bodmer, P. Bochsler, The helium isotopic ratio in the solar wind and ion fractionation in the corona by inefficient Coulomb drag. Astron. Astrophys. 337, 921 (1998).

21. G. Gloeckler, J. Geiss, “Deuterium and helium-3 in the protosolar cloud,” in Light Elements and Their Evolution, L. DaSilva, M. Spite, J. R. DeMedeiros, Eds. (AIU Symposium, 2000), vol. 198, pp. 224–233.

22. V. S. Heber, R. C. Wiens, P. Bochsler, R. Wieler, D. S. Burnett, Fractionation processes in the solar wind revealed by noble gases collected by Genesis regime targets. Lunar Planet. Sci. XL, xxx (2009).

23. R. Kallenbach et al., Fractionation of Si, Ne, and Mg Isotopes in the solar wind as measured by Soho/Celias/MTOF. Space Sci. Rev. 85, 357 (1998).

24. R. Bodmer, P. Bochsler, Influence of Coulomb collisions on isotopic and elemental fractionation in the solar wind acceleration process. J. Geophys. Res. Space Phys. 105, 47 (2000).

25. The hydrogen fluence is derived from the ion monitor on the Genesis spacecraft and the helium fluence is measured in the Genesis target by (52).

26. K. D. McKeegan, L. A. Leshin, in Stable Isotope Geochemistry, J. W. Valley, D. R. Cole, Eds. (Mineralogical Society of America, Washington, DC, 2001), vol. 43, pp. 279–318.

27. A. N. Krot et al., Oxygen isotopic composition of the Sun and mean oxygen isotopic composition of the protosolar silicate dust: Evidence from refractory inclusions. Astrophys. J. 713, 1159 (2010).

28. K. Hashizume, M. Chaussidon, A non-terrestrial 16O-rich isotopic composition for the protosolar nebula. Nature 434, 619 (2005).

29. K. Fujimoto, S. Itoh, S. Ebata, H. Yurimoto, Non-chondritic oxygen isotopic component of metals in a noble-gas-rich chondrite—vestige of stellar wind from the protosun? Geochem. J. 43, e11 (2009).

30. T. R. Ireland, P. Holden, M. D. Norman, J. Clarke, Isotopic enhancements of 17O and 18O from solar wind particles in the lunar regolith. Nature 440, 776 (2006).

31. K. Hashizume, M. Chaussidon, Two oxygen isotopic components with extra-selenial origins observed among lunar metallic grains – In search for the solar wind component. Geochim. Cosmochim. Acta 73, 3038 (2009).

32. T. R. Ayres, C. Plymate, C. U. Keller, Solar carbon monoxide, thermal profiling, and the abundances of C, O, and their isotopes. Astrophys. J. Suppl. Ser. 165, 618 (2006).

33. P. C. Scott, M. Asplund, N. Grevesse, A. J. Sauval, Line formation in solar granulation. Astron. Astrophys. 456, 675 (2006).

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34. If the Sun’s composition lies on the CAI-mixing line, as we hypothesize, then gravitational settling would result in the photosphere being slightly displaced to the left by ~3‰/amu, depending on the model (53).

35. A. Yamada, S. Nanbu, Y. Kasai, M. Ozima, Quantum chemical calculations on photodissociation of CO. Lunar Planet. Sci. XLII, 1707 (2011).

36. K. D. McKeegan, Oxygen isotopes in refractory stratospheric dust particles: proof of extraterrestrial origin. Science 237, 1468 (1987).

37. K. D. McKeegan et al., Isotopic compositions of cometary matter returned by Stardust. Science 314, 1724 (2006).

38. K. D. McKeegan, M. Chaussidon, F. Robert, Incorporation of short-lived 10Be in a calcium-aluminum-rich inclusion from the allende meteorite. Science 289, 1334 (2000).

39. M. Chaussidon, F. Robert, K. D. McKeegan, Li and B isotopic variations in an Allende CAI: Evidence for the in situ decay of short-lived 10Be and for the possible presence of the short-lived nuclide 7Be in the early solar system. Geochim. Cosmochim. Acta 70, 224 (2006).

40. T. J. Fagan, K. D. McKeegan, A. N. Krot, K. Keil, Calcium-aluminum-rich inclusions in enstatite chondrites (II): Oxygen isotopes. Meteorit. Planet. Sci. 36, 223 (2001).

41. Y. Guan, K. D. McKeegan, G. J. MacPherson, Oxygen isotopes in calcium–aluminum-rich inclusions from enstatite chondrites: New evidence for a single CAI source in the solar nebula. Earth Planet. Sci. Lett. 181, 271 (2000).

42. J. R. Lyons et al., Timescales for the evolution of oxygen isotope compositions in the solar nebula. Geochim. Cosmochim. Acta 73, 4998 (2009).

43. E. D. Young, Time-dependent oxygen isotopic effects of CO self shielding across the solar protoplanetary disk. Earth Planet. Sci. Lett. 262, 468 (2007).

44. J. Aléon, C. Engrand, L. A. Leshin, K. D. McKeegan, Oxygen isotopic composition of chondritic interplanetary dust particles: A genetic link between carbonaceous chondrites and comets. Geochim. Cosmochim. Acta 73, 4558 (2009).

45. G. Dominguez, A heterogeneous chemical origin for the 16O-enriched and 16O-depleted reservoirs of the early solar system. Astrophys. J. 713, L59 (2010).

46. R. L. Smith, K. M. Pontoppidan, E. D. Young, M. R. Morris, E. F. van Dishoeck, High-precision C17O, C18O, and C16O measurements in young stellar objects: Analogues for CO self-shielding in the early solar system. Astrophys. J. 701, 163 (2009).

47. K. Kobayashi, H. Imai, H. Yurimoto, New extreme 16O-rich reservoir in the early solar system. Geochem. J. 37, 663 (2003).

48. M. H. Thiemens, J. E. Heidenreich III, The mass-independent fractionation of oxygen: A novel isotope effect and its possible cosmochemical implications. Science 219, 1073 (1983).

49. M. H. Thiemens, T. L. Jackson, C. A. M. Brenninkmeijer, Observation of a mass independent oxygen isotopic composition in terrestrial stratospheric CO2, the link to

15

ozone chemistry, and the possible occurrence in the Martian atmosphere. Geophys. Res. Lett. 22, 255 (1995).

50. A. Ali, J. A. Nuth, The oxygen isotope effect in the earliest processed solids in the solar system: Is it a chemical mass-independent process? Astron. Astrophys. 467, 919 (2007).

51. B. Marty, M. Chaussidon, R. C. Wiens, A. J. G. Jurewicz, D. S. Burnett, A 15N-poor isotopic composition for the solar system as shown by Genesis solar wind samples. Science 332, 1533 (2011).

52. V. S. Heber et al., Noble gas composition of the solar wind as collected by the Genesis mission. Geochim. Cosmochim. Acta 73, 7414 (2009).

53. S. Turcotte, R. F. Wimmer-Schweingruber, Possible in situ tests of the evolution of elemental and isotopic abundances in the solar convection zone. J. of Geophys. Res. 107, 1442 (2002).

54. A. J. G. Jurewicz et al., The Genesis solar-wind collector materials. Space Sci. Rev. 105, 535 (2003).

55. M. C. Liu et al., Isotopic records in CM hibonites: Implications for timescales of mixing of isotope reservoirs in the solar nebula. Geochim. Cosmochim. Acta 73, 5051 (2009).

56. B. G. Choi, K. D. McKeegan, A. N. Krot, J. T. Wasson, Extreme oxygen-isotope compositions in magnetite from unequilibrated ordinary chondrites. Nature 392, 577 (1998).

57. E. D. Young, S. S. Russell, Oxygen reservoirs in the early solar nebula inferred from an Allende CAI. Science 282, 452 (1998).

58. J. E. Nordholt et al., The Genesis solar wind Concentrator. Space Sci. Rev. 105, 561 (2003).

59. J. Aléon, Nancy-Universite (2001).

60. R. N. Clayton, T. K. Mayeda, Oxygen isotope studies of achondrites. Geochim. Cosmochim. Acta 60, 1999 (1996).

61. L. A. Leshin, A. E. Rubin, K. D. McKeegan, The oxygen isotopic composition of olivine and pyroxene from CI chondrites. Geochim. Cosmochim. Acta 61, 835 (1997).

62. R. C. Wiens, C. T. Olinger, D. Reisenfeld, Ion trajectory simulations of the Genesis solar wind Concentrator performance. Lunar Planet. Sci. XLII, 1555 (2011).