Ultra-Heavy Galactic Cosmic Ray Measurements and Source Abundances Analysis Progress for Both SuperTIGER Flights

Oral-In-person

Abstract

Galactic Cosmic Ray (GCR) measurements up to $_{40}$Zr support a model in which GCR are accelerated from their source of 80$\%$ interstellar medium and 20$\%$ massive star material by supernovae in OB associations. Refractory elements, which more readily condense onto interstellar dust grains, are preferentially accelerated over volatiles. SuperTIGER (Super Trans-Iron Galactic Element Recorder) is a long-duration balloon-borne instrument designed to measure GCRs with resolved single element peaks from $_{10}$Ne to $_{40}$Zr and low statistics measurements up to $_{56}$Ba.  SuperTIGER had two successful Antarctic flights: the first in 2012 for 55 days and the second in 2019 for 32 days. We report elemental abundances for $_{10}$Zr to $_{56}$Ba for the first SuperTIGER flight and their corresponding derived top-of-atmosphere (TOA) and Galactic Cosmic-Ray Source (GCRS) abundances and we report analysis progress for the second flight. GCR measurements above $_{40}$Zr show a break in the preferential acceleration of refractory elements, hinting to a different source or acceleration mechanism for elements above $_{40}$Zr. Future GCR measurements above $_{40}$Zr are important in constraining this multifaceted problem.

Presenters

  • Nicole Osborn

    • Washington University, St. Louis

Authors

  • Nicole Osborn

    • Washington University, St. Louis
  • Brian Rauch

    • Washington University, St. Louis
  • Wolfgang Zober

    • Washington University, St. Louis