title: The oxygen isotopic composition of the Sun inferred from captured solar wind.
abstract: All planetary materials sampled thus far vary in their relative abundance of the major isotope of oxygen, (16)O, such that it has not been possible to define a primordial solar system composition. We measured the oxygen isotopic composition of solar wind captured and returned to Earth by NASA's Genesis mission. Our results demonstrate that the Sun is highly enriched in (16)O relative to the Earth, Moon, Mars, and bulk meteorites. Because the solar photosphere preserves the average isotopic composition of the solar system for elements heavier than lithium, we conclude that essentially all rocky materials in the inner solar system were enriched in (17)O and (18)O, relative to (16)O, by ~7%, probably via non-mass-dependent chemistry before accretion of the first planetesimals.
authors.affiliation: Department of Earth and Space Sciences, University of California-Los Angeles (UCLA), Los Angeles, CA 90095-1567, USA. mckeegan@ess.ucla.edu
authors.forename: K D
authors.initials: KD
authors.lastname: McKeegan
authors.forename: A P A
authors.initials: AP
authors.lastname: Kallio
authors.forename: V S
authors.initials: VS
authors.lastname: Heber
authors.forename: G
authors.initials: G
authors.lastname: Jarzebinski
authors.forename: P H
authors.initials: PH
authors.lastname: Mao
authors.forename: C D
authors.initials: CD
authors.lastname: Coath
authors.forename: T
authors.initials: T
authors.lastname: Kunihiro
authors.forename: R C
authors.initials: RC
authors.lastname: Wiens
authors.forename: J E
authors.initials: JE
authors.lastname: Nordholt
authors.forename: R W
authors.initials: RW
authors.lastname: Moses
authors.forename: D B
authors.initials: DB
authors.lastname: Reisenfeld
authors.forename: A J G
authors.initials: AJ
authors.lastname: Jurewicz
authors.forename: D S
authors.initials: DS
authors.lastname: Burnett