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Title: ISOTOPIC MASS FRACTIONATION OF SOLAR WIND: EVIDENCE FROM FAST AND SLOW SOLAR WIND COLLECTED BY THE GENESIS MISSION

Abstract

NASA's Genesis space mission returned samples of solar wind collected over {approx}2.3 years. We present elemental and isotopic compositions of He, Ne, and Ar analyzed in diamond-like carbon targets from the slow and fast solar wind collectors to investigate isotopic fractionation processes during solar wind formation. The solar wind provides information on the isotopic composition for most volatile elements for the solar atmosphere, the bulk Sun and hence, on the solar nebula from which it formed 4.6 Ga ago. Our data reveal a heavy isotope depletion in the slow solar wind compared to the fast wind composition by 63.1 {+-} 2.1 per mille for He, 4.2 {+-} 0.5 per mille amu{sup -1} for Ne and 2.6 {+-} 0.5 per mille amu{sup -1} for Ar. The three Ne isotopes suggest that isotopic fractionation processes between fast and slow solar wind are mass dependent. The He/H ratios of the collected slow and fast solar wind samples are 0.0344 and 0.0406, respectively. The inefficient Coulomb drag model reproduces the measured isotopic fractionation between fast and slow wind. Therefore, we apply this model to infer the photospheric isotopic composition of He, Ne, and Ar from our solar wind data. We also compare the isotopicmore » composition of oxygen and nitrogen measured in the solar wind with values of early solar system condensates, probably representing solar nebula composition. We interpret the differences between these samples as being due to isotopic fractionation during solar wind formation. For both elements, the magnitude and sign of the observed differences are in good agreement with the values predicted by the inefficient Coulomb drag model.« less

Authors:
; ;  [1];  [2];  [3];  [4];  [5];  [6]
  1. Institute for Geochemistry and Petrology, ETH Zurich, Clausiusstrasse 25, CH-8092 Zurich (Switzerland)
  2. Physikalisches Institut, Universitaet Bern, Sidlerstasse 5, CH-3012 Bern (Switzerland)
  3. Department of Earth and Space Sciences, University of California Los Angeles, 595 Charles Young Drive East, Box 951567, Los Angeles, CA 90095-1567 (United States)
  4. Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721-0092 (United States)
  5. Department of Physics and Astronomy, University of Montana, Missoula, MT 59812 (United States)
  6. Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
Publication Date:
OSTI Identifier:
22086402
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 759; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; ELEMENT ABUNDANCE; FRACTIONATION; HYDROGEN; ISOTOPE RATIO; MASS; NEON ISOTOPES; NITROGEN; OXYGEN; PHOTOSPHERE; SOLAR NEBULA; SOLAR SYSTEM; SOLAR WIND; SUN

Citation Formats

Heber, Veronika S., Baur, Heinrich, Wieler, Rainer, Bochsler, Peter, McKeegan, Kevin D., Neugebauer, Marcia, Reisenfeld, Daniel B., and Wiens, Roger C., E-mail: heber@ess.ucla.edu. ISOTOPIC MASS FRACTIONATION OF SOLAR WIND: EVIDENCE FROM FAST AND SLOW SOLAR WIND COLLECTED BY THE GENESIS MISSION. United States: N. p., 2012. Web. doi:10.1088/0004-637X/759/2/121.
Heber, Veronika S., Baur, Heinrich, Wieler, Rainer, Bochsler, Peter, McKeegan, Kevin D., Neugebauer, Marcia, Reisenfeld, Daniel B., & Wiens, Roger C., E-mail: heber@ess.ucla.edu. ISOTOPIC MASS FRACTIONATION OF SOLAR WIND: EVIDENCE FROM FAST AND SLOW SOLAR WIND COLLECTED BY THE GENESIS MISSION. United States. doi:10.1088/0004-637X/759/2/121.
Heber, Veronika S., Baur, Heinrich, Wieler, Rainer, Bochsler, Peter, McKeegan, Kevin D., Neugebauer, Marcia, Reisenfeld, Daniel B., and Wiens, Roger C., E-mail: heber@ess.ucla.edu. Sat . "ISOTOPIC MASS FRACTIONATION OF SOLAR WIND: EVIDENCE FROM FAST AND SLOW SOLAR WIND COLLECTED BY THE GENESIS MISSION". United States. doi:10.1088/0004-637X/759/2/121.
@article{osti_22086402,
title = {ISOTOPIC MASS FRACTIONATION OF SOLAR WIND: EVIDENCE FROM FAST AND SLOW SOLAR WIND COLLECTED BY THE GENESIS MISSION},
author = {Heber, Veronika S. and Baur, Heinrich and Wieler, Rainer and Bochsler, Peter and McKeegan, Kevin D. and Neugebauer, Marcia and Reisenfeld, Daniel B. and Wiens, Roger C., E-mail: heber@ess.ucla.edu},
abstractNote = {NASA's Genesis space mission returned samples of solar wind collected over {approx}2.3 years. We present elemental and isotopic compositions of He, Ne, and Ar analyzed in diamond-like carbon targets from the slow and fast solar wind collectors to investigate isotopic fractionation processes during solar wind formation. The solar wind provides information on the isotopic composition for most volatile elements for the solar atmosphere, the bulk Sun and hence, on the solar nebula from which it formed 4.6 Ga ago. Our data reveal a heavy isotope depletion in the slow solar wind compared to the fast wind composition by 63.1 {+-} 2.1 per mille for He, 4.2 {+-} 0.5 per mille amu{sup -1} for Ne and 2.6 {+-} 0.5 per mille amu{sup -1} for Ar. The three Ne isotopes suggest that isotopic fractionation processes between fast and slow solar wind are mass dependent. The He/H ratios of the collected slow and fast solar wind samples are 0.0344 and 0.0406, respectively. The inefficient Coulomb drag model reproduces the measured isotopic fractionation between fast and slow wind. Therefore, we apply this model to infer the photospheric isotopic composition of He, Ne, and Ar from our solar wind data. We also compare the isotopic composition of oxygen and nitrogen measured in the solar wind with values of early solar system condensates, probably representing solar nebula composition. We interpret the differences between these samples as being due to isotopic fractionation during solar wind formation. For both elements, the magnitude and sign of the observed differences are in good agreement with the values predicted by the inefficient Coulomb drag model.},
doi = {10.1088/0004-637X/759/2/121},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 759,
place = {United States},
year = {2012},
month = {11}
}