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Elemental Abundances of Major Elements in the Solar Wind as Measured in Genesis Targets and Implications on Solar Wind Fractionation

Heber, Veronika S. and McKeegan, Kevin D. and Steele, Robert C. J. and Jurewicz, Amy J. G. and Rieck, Karen D. and Guan, Yunbin and Wieler, Rainer and Burnett, Donald S. (2021) Elemental Abundances of Major Elements in the Solar Wind as Measured in Genesis Targets and Implications on Solar Wind Fractionation. Astrophysical Journal, 907 (1). Art. No. 15. ISSN 1538-4357. PMCID PMC8350966. doi:10.3847/1538-4357/abc94a.

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We present elemental abundance data of C, N, O, Na, Mg, Al, Ca, and Cr in Genesis silicon targets. For Na, Mg, Al, and Ca, data from three different solar wind (SW) regimes are also presented. Data were obtained by backside depth profiling using secondary ion mass spectrometry. The accuracy of these measurements exceeds those obtained by in situ observations; therefore, the Genesis data provide new insights into elemental fractionation between Sun and SW, including differences between SW regimes. We integrate previously published noble gas and hydrogen elemental abundances from Genesis targets, as well as preliminary values for K and Fe. The abundances of the SW elements measured display the well-known fractionation pattern that correlates with each element's first-ionization potential (FIP). When normalized either to spectroscopic photospheric solar abundances or to those derived from CI-chondritic meteorites, the fractionation factors of low-FIP elements (K, Na, Al, Ca, Cr, Mg, Fe) are essentially identical within uncertainties, but the data are equally consistent with increasing fractionation with decreasing FIP. The elements with higher FIPs between ~11 and ~16 eV (C, N, O, H, Ar, Kr, Xe) display a relatively well-defined trend of increasing fractionation with decreasing FIP, if normalized to modern 3D photospheric model abundances. Among the three Genesis regimes, the fast SW displays the least elemental fractionation for almost all elements (including the noble gases) but differences are modest: for low-FIP elements, the precisely measured fast–slow SW variations are less than 3%.

Item Type:Article
Related URLs:
URLURL TypeDescription CentralArticle
McKeegan, Kevin D.0000-0002-1827-729X
Steele, Robert C. J.0000-0003-1406-6855
Jurewicz, Amy J. G.0000-0002-3282-5782
Rieck, Karen D.0000-0002-7427-9134
Guan, Yunbin0000-0002-7636-3735
Wieler, Rainer0000-0001-5666-7494
Burnett, Donald S.0000-0001-9521-8675
Additional Information:© 2021. The American Astronomical Society. Received 2020 September 8; revised 2020 October 27; accepted 2020 November 9; published 2021 January 20. We appreciate the expertise and cooperation of the curatorial team at NASA Johnson Space Center in cleaning the Genesis collector fragments. D. Ledu, F. Fortuna (CSNSM Orsay), E. Briand, and J.-J. Ganem (Universités Pierre et Marie Curie and Namur) are thanked for standard implantations and nuclear reaction analyses. We appreciate discussions with P. Bochsler and comments and suggestions by the reviewer. The UCLA ion microprobe facility is partially supported by a grant from the NSF Instrumentation and Facilities program. V.S.H. thanks NASA for financial support. This work was supported by grants from the NASA Laboratory Analysis of Returned Samples (LARS) program (NASA LARS 80NSSC17K0025 to D.S.B. and A.J.G.J. R.W. acknowledges the hospitality of Caltech's Division of Geological and Planetary Sciences during his stay in Pasadena.
Funding AgencyGrant Number
Subject Keywords:Solar wind ; Solar abundances ; Fast solar wind ; Slow solar wind ; Solar coronal mass ejections ; Chemical abundances
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: Solar wind (1534); Solar abundances (1474); Fast solar wind (1872); Slow solar wind (1873); Solar coronal mass ejections (310); Chemical abundances (224)
PubMed Central ID:PMC8350966
Record Number:CaltechAUTHORS:20210121-101410476
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Official Citation:Veronika S. Heber et al 2021 ApJ 907 15
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:107625
Deposited By: George Porter
Deposited On:21 Jan 2021 21:45
Last Modified:08 Feb 2022 22:43

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