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Title: The Ne-to-O abundance ratio of the interstellar medium from IBEX-Lo observations

In this paper we report on a two-year study to estimate the Ne/O abundance ratio in the gas phase of the local interstellar cloud (LIC). Based on the first two years of observations with the Interstellar Boundary Explorer, we determined the fluxes of interstellar neutral (ISN) O and Ne atoms at the Earth's orbit in spring 2009 and 2010. A temporal variation of the Ne/O abundance ratio at the Earth's orbit could be expected due to solar cycle-related effects such as changes of ionization. However, this study shows that there is no significant change in the Ne/O ratio at the Earths orbit from 2009 to 2010. We used time-dependent survival probabilities of the ISNs to calculate the Ne/O abundance ratio at the termination shock. Then we estimated the Ne/O abundance ratio in the gas phase of the LIC with the use of filtration factors and the ionization fractions. From our analysis, the Ne/O abundance ratio in the LIC is 0.33 ± 0.07, which is in agreement with the abundance ratio inferred from pickup-ion measurements.
Authors:
; ; ;  [1] ; ; ;  [2] ; ;  [3]
  1. Space Science Center and Department of Physics, University of New Hampshire, 8 College Road, Durham, NH 03824 (United States)
  2. Space Research Centre of the Polish Academy of Science, Bartycka 18A, 00-716 Warsaw (Poland)
  3. Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228 (United States)
Publication Date:
OSTI Identifier:
22370281
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 795; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; ATOMS; CONCENTRATION RATIO; COSMIC GASES; COSMOLOGY; ELEMENT ABUNDANCE; FILTRATION; INTERSTELLAR SPACE; NEON; ORBITS; OXYGEN; PROBABILITY; SOLAR CYCLE; TIME DEPENDENCE