Reliability of Zodiacal Background Models at Small Solar Elongations
Abstract
Present models of the zodiacal light (scattered sunlight from interplanetary dust in the visible) and zodiacal emission (thermal emission in the mid-infrared) are primarily constrained by surface-brightness measurements obtained at relatively large solar elongations (e >~ 60 deg). As a result, their predictive accuracy at smaller elongations remains uncertain. This is particularly relevant for solar elongations of e ~ 30-60 deg, where next-generation near-Earth-object discovery missions such as NEO Surveyor and NEOMIR are designed to operate. To evaluate the reliability of these models at small solar elongations, we compile and reanalyze the available small-elongation zodiacal-light and zodiacal-emission measurements and provide the first systematic validation of modern zodiacal-light models in a regime where they have never been independently tested. We compare two models derived from the COBE/DIRBE survey: one constrained primarily by the spatial and temporal variation of the monochromatic sky brightness, and another that additionally uses interband color information and fixes the absolute normalization by requiring the minimum high-latitude residual at 25um to vanish. We find that the former reproduces the observations significantly better. At wavelengths most relevant to infrared near-Earth-object surveys (8-10 um), it typically agrees with measurements to within ~10% at e ~ 40-60 deg. Although it also performs better at e ~ 30 deg, significant discrepancies remain. These results show that zodiacal emission at small solar elongations is still only weakly constrained and that its absolute brightness remains uncertain. New mid-infrared observations are required to improve background estimates for future infrared survey missions.
Related
- Twenty-five years of XMM-Newton EPIC-MOS2 Unfocused Particle Background: Solar Cycle Modulation, Galactic Cosmic-Ray Correlation, and Implications for NewAthena
- Large-scale Vortices in the Solar Photosphere: Statistical Properties and the Reliability of Local Correlation Tracking
- Large-scale Vortices in the Solar Photosphere: Statistical Properties and the Reliability of Local Correlation Tracking
- Investigating the formation of small Solar System objects using stellar occultations by satellites: present, future and its use to update satellite orbits
- Application of Nonspherical Dust Models to Polarization of Zodiacal Light Observed with DIRBE/COBE
BibTeX
@misc{kiss2026reliability,
title = {{Reliability of Zodiacal Background Models at Small Solar Elongations}},
author = {Csaba Kiss and Thomas G. Müller and Javier Licandro and Luca Conversi and Marco Delbo and Karri Muinonen and Marcel Popescu and Paolo Tanga and Róbert Szakáts},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.19925},
eprint = {2609.19925},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.19925},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Reliability of Zodiacal Background Models at Small Solar Elongations
AU - Csaba Kiss
AU - Thomas G. Müller
AU - Javier Licandro
AU - Luca Conversi
AU - Marco Delbo
AU - Karri Muinonen
AU - Marcel Popescu
AU - Paolo Tanga
AU - Róbert Szakáts
PY - 2026
DA - 2026/09/17
PB - arXiv
DO - 10.48550/arxiv.2609.19925
UR - https://arxiv.org/abs/2609.19925
AB - Present models of the zodiacal light (scattered sunlight from interplanetary dust in the visible) and zodiacal emission (thermal emission in the mid-infrared) are primarily constrained by surface-brightness measurements obtained at relatively large solar elongations (e >~ 60 deg). As a result, their predictive accuracy at smaller elongations remains uncertain. This is particularly relevant for solar elongations of e ~ 30-60 deg, where next-generation near-Earth-object discovery missions such as NEO Surveyor and NEOMIR are designed to operate. To evaluate the reliability of these models at small solar elongations, we compile and reanalyze the available small-elongation zodiacal-light and zodiacal-emission measurements and provide the first systematic validation of modern zodiacal-light models in a regime where they have never been independently tested. We compare two models derived from the COBE/DIRBE survey: one constrained primarily by the spatial and temporal variation of the monochromatic sky brightness, and another that additionally uses interband color information and fixes the absolute normalization by requiring the minimum high-latitude residual at 25um to vanish. We find that the former reproduces the observations significantly better. At wavelengths most relevant to infrared near-Earth-object surveys (8-10 um), it typically agrees with measurements to within ~10% at e ~ 40-60 deg. Although it also performs better at e ~ 30 deg, significant discrepancies remain. These results show that zodiacal emission at small solar elongations is still only weakly constrained and that its absolute brightness remains uncertain. New mid-infrared observations are required to improve background estimates for future infrared survey missions.
ER -