Heliocentric Distance Dependence of Zodiacal Light Observed by Hayabusa2#

Abstract

Zodiacal light (ZL) is sunlight scattered by interplanetary dust particles (IDPs) at optical wavelengths. The spatial distribution of IDPs in the Solar System may hold an important key to understanding the evolution of the Solar System and material transportation within it. The number density of IDPs can be expressed as $n(r)\sim r^{-\alpha }$, and the exponent $\alpha \sim 1.3$ was obtained by previous observations from interplanetary space by Helios 1/2 and Pioneer 10/11 in the 1970s and 1980s. However, no direct measurements of $\alpha$ based on ZL observations from interplanetary space outside Earth's orbit have been performed since then. Here, we introduce initial results for the radial profile of the ZL at optical wavelengths observed over the range 0.76-1.06 au by ONC-T aboard the Hayabusa2# mission in 2021-2022. The ZL brightness we obtained is well reproduced by a model brightness, although there is a small excess of the observed ZL brightness over the model brightness at around 0.9 au. The radial power-law index we obtained is $\alpha =1.30\pm 0.08$, which is consistent with previous results based on ZL observations. The dominant source of uncertainty arises from the uncertainty in estimating the diffuse Galactic light (DGL).

22 pages, 19 figures, 4 tables, accepted for publication by Earth, Planets and Space

References in corpus (25)

• The Gaia mission
• Gaia Data Release 3: Summary of the content and survey properties
• Gaia Early Data Release 3: Photometric content and validation
• JWST's PEARLS: Prime Extragalactic Areas for Reionization and Lensing Science: Project Overview and First Results
• Long-Range Reconnaissance Imager on New Horizons
• On the Origin of Near-Infrared Extragalactic Background Light Anisotropy
• The $AKARI$ Far-Infrared All-Sky Survey Maps
• Anomalous Flux in the Cosmic Optical Background Detected With New Horizons Observations
• The Near-Sun Dust Environment: Initial Observations from Parker Solar Probe
• Extended Red Emission in High-Galactic Latitude Interstellar Clouds
• Hayabusa2 Extended Mission: New Voyage to Rendezvous with a Small Asteroid Rotating with a Short Period
• Extragalactic background Light: a measurement at 400 nm using dark cloud shadow II. Spectroscopic separation of dark cloud's light, and results
• Ultraviolet to optical diffuse sky emission as seen by the Hubble Space Telescope Faint Object Spectrograph
• Calibration of the AKARI Far-infrared All Sky Survey Maps
• Measurements of the mean diffuse galactic light spectrum in the 0.95 μm to 1.65 μm band from CIBER
• A Measurement of the Cosmic Optical Background and Diffuse Galactic Light Scaling from the R < 50 AU New Horizons-LORRI Data
• SKYSURF: Constraints on Zodiacal Light and Extragalactic Background Light through Panchromatic HST All-Sky Surface-Brightness Measurements: I. Survey Overview and Methods
• Zodiacal light observations and its link with cosmic dust: a review
• Can decaying particle explain cosmic infrared background excess?
• Measurements of the Zodiacal Light Absolute Intensity through Fraunhofer Absorption Line Spectroscopy with CIBER
• Cosmoglobe: Simulating zodiacal emission with ZodiPy
• Polarization spectrum of near infrared zodiacal light observed with CIBER
• Near-infrared Polarization Charateristics of the Zodiacal Light Observed with DIRBE/COBE
• On the origin of the optical and near-infrared extragalactic background light
• Looking for the Signals of the Missing Baryons in the Extragalactic Background Light