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

McKeegan, K. D.; Kallio, Antti; Heber, V. S.; Jarzebinski, G.; Mao, P. H.; Coath, C. D.; Kunihiro, T.; Wiens, R. C.; Nordholt, J. E.; Moses, RW; Reisenfeld, D. B.; Jurewicz, A. J. G.; Burnett, D. S.

doi:10.1126/science.1204636

Cited by 350 publications

(329 citation statements)

References 53 publications

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“…[5][6][7][8][9] Observations have shown that the rare heavy isotopes for both O and N are enriched on the Earth compared with the sun and solar nebula. 10,11 A similar behavior is expected in the interstellar medium as well as around young stars. The 15 N isotope is more enriched (about 40%) on the Earth than 17 O (about 6%) but the reason why it is so is not yet understood.…”

Section: Introductionmentioning

confidence: 49%

Communication: Branching ratio measurements in the predissociation of 12C16O by time-slice velocity-map ion imaging in the vacuum ultraviolet region

Gao

Song

Yang

et al. 2011

The Journal of Chemical Physics

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The first direct branching ratio measurement of the three lowest energy dissociation channels of CO that produce C( 3 P) + O( 3 P), C( 1 D) + O( 3 P), and C( 3 P) + O( 1 D) is reported. Rotational resolved carbon ion yield spectra for two bands (W(3sσ ) 1 (v = 3) at 108 012.6 cm −1 and 1 (v = 2) at 109 017 cm −1 ) and two bands ((4sσ ) 1 + (v = 4) at 109 452 cm −1 and (4pσ ) 1 + (v = 3) at 109 485 cm −1 ) of CO were obtained. Our measurements show that the branching ratio in this energy region is strongly dependent on the electronic and vibrational energy but it is independent or just weakly dependent on the parity and rotational energy levels. To our knowledge, this is the first time that the triplet channel producing O( 1 D) has been experimentally observed and this is also the first time that a direct measurement of the branching ratio for the different channels in the predissociation of CO in this energy region has been made.

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Section: Introductionmentioning

confidence: 49%

Communication: Branching ratio measurements in the predissociation of 12C16O by time-slice velocity-map ion imaging in the vacuum ultraviolet region

Gao

Song

Yang

et al. 2011

The Journal of Chemical Physics

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“…A galactic origin for the initial abundance of 182 Hf recorded by the FUN and canonical CAIs requires ∼18 Ma of free decay between last nucleosynthetic event that produced the heavy (31), the oxygen-isotope compositions of anorthite, spinel, hibonite, and most Al,Ti-diopside grains in STP-1 plot along a massdependent fractionation line defining an initial Δ 17 O value of ∼ −24‰, that is, similar to the oxygen-isotope composition of canonical CAIs and that of the Sun (31,32). Oxygen-isotope compositions of melilite and some of the Al,Ti-diopside grains plot along a line with a slope of ∼1, suggesting subsequent isotope exchange with a 16 O-depleted gaseous reservoir.…”

Section: Resultsmentioning

confidence: 99%

¹⁸² Hf– ¹⁸² W age dating of a ²⁶ Al-poor inclusion and implications for the origin of short-lived radioisotopes in the early Solar System

Holst

Olsen

Paton

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Refractory inclusions [calcium–aluminum-rich inclusions, (CAIs)] represent the oldest Solar System solids and provide information regarding the formation of the Sun and its protoplanetary disk. CAIs contain evidence of now extinct short-lived radioisotopes (e.g., 26 Al, 41 Ca, and 182 Hf) synthesized in one or multiple stars and added to the protosolar molecular cloud before or during its collapse. Understanding how and when short-lived radioisotopes were added to the Solar System is necessary to assess their validity as chronometers and constrain the birthplace of the Sun. Whereas most CAIs formed with the canonical abundance of 26 Al corresponding to 26 Al/ 27 Al of ∼5 × 10 −5 , rare CAIs with fractionation and unidentified nuclear isotope effects (FUN CAIs) record nucleosynthetic isotopic heterogeneity and 26 Al/ 27 Al of <5 × 10 −6 , possibly reflecting their formation before canonical CAIs. Thus, FUN CAIs may provide a unique window into the earliest Solar System, including the origin of short-lived radioisotopes. However, their chronology is unknown. Using the 182 Hf– 182 W chronometer, we show that a FUN CAI recording a condensation origin from a solar gas formed coevally with canonical CAIs, but with 26 Al/ 27 Al of ∼3 × 10 −6 . The decoupling between 182 Hf and 26 Al requires distinct stellar origins: steady-state galactic stellar nucleosynthesis for 182 Hf and late-stage contamination of the protosolar molecular cloud by a massive star(s) for 26 Al. Admixing of stellar-derived 26 Al to the protoplanetary disk occurred during the epoch of CAI formation and, therefore, the 26 Al– 26 Mg systematics of CAIs cannot be used to define their formation interval. In contrast, our results support 182 Hf homogeneity and chronological significance of the 182 Hf– 182 W clock.

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“…Detailed thermo-chemical models confirm that this can have a significant impact on the C 18 O emission from low-mass disks though not for such massive disks as HD 163296 (Miotello et al 2014). Future observations of T Tauri disks can examine this important effect and assess whether it may explain the variation of oxygen isotopes in the Solar System (McKeegan et al 2011). …”

Section: As a Rare Isotopologue Cmentioning

confidence: 99%

Measuring Protoplanetary Disk Gas Surface Density Profiles With Alma

Williams

McPartland

2016

ApJ

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The gas and dust are spatially segregated in protoplanetary disks due to the vertical settling and radial drift of large grains. A fuller accounting of the mass content and distribution in disks therefore requires spectral line observations. We extend the modeling approach presented in Williams & Best (2014) to show that gas surface density profiles can be measured from high fidelity 13 CO integrated intensity images. We demonstrate the methodology by fitting ALMA observations of the HD 163296 disk to determine a gas mass, M gas = 0.048 M , and accretion disk characteristic size R c = 213 au and gradient γ = 0.39. The same parameters match the C 18 O 2-1 image and indicates an abundance ratio [ 13 CO]/[C 18 O] of 700 independent of radius. To test how well this methodology can be applied to future line surveys of smaller, lower mass T Tauri disks, we create a large 13 CO 2-1 image library and fit simulated data. For disks with gas masses 3 − 10 M Jup at 150 pc, ALMA observations with a resolution of 0. 2−0. 3 and integration times of ∼ 20 minutes allow reliable estimates of R c to within about 10 au and γ to within about 0.2. Economic gas imaging surveys are therefore feasible and offer the opportunity to open up a new dimension for studying disk structure and its evolution toward planet formation.

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

Cited by 350 publications

References 53 publications

Communication: Branching ratio measurements in the predissociation of 12C16O by time-slice velocity-map ion imaging in the vacuum ultraviolet region

Communication: Branching ratio measurements in the predissociation of 12C16O by time-slice velocity-map ion imaging in the vacuum ultraviolet region

¹⁸² Hf– ¹⁸² W age dating of a ²⁶ Al-poor inclusion and implications for the origin of short-lived radioisotopes in the early Solar System

Measuring Protoplanetary Disk Gas Surface Density Profiles With Alma

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

Cited by 350 publications

References 53 publications

Communication: Branching ratio measurements in the predissociation of 12C16O by time-slice velocity-map ion imaging in the vacuum ultraviolet region

Communication: Branching ratio measurements in the predissociation of 12C16O by time-slice velocity-map ion imaging in the vacuum ultraviolet region

182 Hf– 182 W age dating of a 26 Al-poor inclusion and implications for the origin of short-lived radioisotopes in the early Solar System

Measuring Protoplanetary Disk Gas Surface Density Profiles With Alma

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¹⁸² Hf– ¹⁸² W age dating of a ²⁶ Al-poor inclusion and implications for the origin of short-lived radioisotopes in the early Solar System