Is the Infrared Background Excess Explained by the Isotropic Zodiacal Light from the Outer Solar System?

TL;DR

This study assesses whether isotropic zodiacal light from outer Solar system dust can explain the near-infrared background excess, concluding it cannot account for the observed excess despite considering maximum dust amounts.

Contribution

It provides a quantitative analysis showing that outer Solar system zodiacal light cannot explain the near-infrared background excess.

Findings

Thermal emission peaks at far-infrared (~100 microns) for cold dust in the outer Solar system.

Calculated emission from the dust shell is insufficient to explain the near-infrared excess.

Even with maximum dust assumptions, the isotropic zodiacal light does not account for the observed background excess.

Abstract

This paper investigates whether an isotropic zodiacal light from the outer Solar system can account for the detected background excess in near-infrared. Assuming that interplanetary dust particles are distributed in a thin spherical shell at the outer Solar system (>200 AU), thermal emission from such cold (<30 K) dust in the shell has a peak at far-infrared (~100 microns). By comparing the calculated thermal emission from the dust shell with the observed background emissions at far-infrared, permissible dust amount in the outer Solar system is obtained. Even if the maximum dust amount is assumed, the isotropic zodiacal light as the reflected sunlight from the dust shell at the outer Solar system cannot explain the detected background excess at near-infrared.