On the Geometry of the IBEX Ribbon

TL;DR

This paper presents an analytical model demonstrating that the IBEX ENA ribbon's location is consistent with a neutral density enhancement in the local interstellar medium, explaining its formation.

Contribution

It introduces a quantitative analytical model linking the IBEX ribbon to a neutral density enhancement in the interstellar medium, supporting the H-wave hypothesis.

Findings

Model aligns with observed ribbon location across energies

Supports the H-wave hypothesis for ribbon formation

Provides a consistent explanation for the ribbon's geometry

Abstract

The Energetic Neutral Atom (ENA) full-sky maps obtained with the Interstellar Boundary Explorer (IBEX) show an unexpected bright narrow band of increased intensity. This so-called ENA ribbon results from charge exchange of interstellar neutral atoms with protons in the outer heliosphere or beyond. Amongst other hypotheses it has been argued that this ribbon may be related to a neutral density enhancement, or H-wave, in the local interstellar medium. Here we quantitatively demonstrate, on the basis of an analytical model of the principal large-scale heliospheric structure, that this scenario for the ribbon formation leads to results that are fully consistent with the observed location of the ribbon in the full-sky maps at all energies detected with high-energy sensor IBEX-Hi.