The isotopic composition and fluence of solar-wind nitrogen in a genesis B/C array collector

Authors

  • Gary R. HUSS,

    Corresponding author
    1. Hawai’i Institute of Geophysics and Planetology, University of Hawai’i at Mānoa, 1680 East-West Road, POST 504, Honolulu, Hawai’i 96822, USA
    Search for more papers by this author
  • Kazuhide NAGASHIMA,

    1. Hawai’i Institute of Geophysics and Planetology, University of Hawai’i at Mānoa, 1680 East-West Road, POST 504, Honolulu, Hawai’i 96822, USA
    Search for more papers by this author
  • Amy J. G. JUREWICZ,

    1. Center for Meteorite Studies, Arizona State University, 550 East Tyler Mall, PSF-686, Tempe, Arizona 85287–1404, USA
    Search for more papers by this author
  • Donald S. BURNETT,

    1. Division of Geological and Planetary Science, California Institute of Technology, Mail Code 100-23, 1200 E. California Blvd., Pasadena, California 91125, USA
    Search for more papers by this author
  • Chad T. OLINGER

    1. Applied Modern Physics, Los Alamos National Laboratory (MS D434), Los Alamos, New Mexico 98544, USA
    Search for more papers by this author

Corresponding author. E-mail: ghuss@higp.hawaii.edu

Abstract

Abstract–  We have measured the isotopic composition and fluence of solar-wind nitrogen in a diamond-like-carbon collector from the Genesis B/C array. The B and C collector arrays on the Genesis spacecraft passively collected bulk solar wind for the entire collection period, and there is no need to correct data for instrumental fractionation during collection, unlike data from the Genesis “Concentrator.” This work validates isotopic measurements from the concentrator by Marty et al. (2010, 2011); nitrogen in the solar wind is depleted in 15N relative to nitrogen in the Earth’s atmosphere. Specifically, our array data yield values for 15N/14N of (2.17 ± 0.37) × 10−3 and (2.12 ± 0.34) × 10−3, depending on data-reduction technique. This result contradicts preliminary results reported for previous measurements on B/C array materials by Pepin et al. (2009), so the discrepancy between Marty et al. (2010, 2011) and Pepin et al. (2009) was not due to fractionation of solar wind by the concentrator. Our measured value of 15N/14N in the solar wind shows that the Sun, and by extension the solar nebula, lie at the low-15N/14N end of the range of nitrogen isotopic compositions observed in the solar system. A global process (or combination of processes) must have operated in interstellar space and/or during the earliest stages of solar system formation to increase the 15N/14N ratio of the solar system solids. We also report a preliminary Genesis solar-wind nitrogen fluence of (2.57 ± 0.42) × 1012 cm−2. This value is higher than that derived by backside profiling of a Genesis silicon collector (Heber et al. 2011a).

Ancillary