Large-scale Morphology of the Optical F-corona from a Total Solar Eclipse Observation During the Artemis II Lunar Flyby

Original Abstract

We investigate the structure of the optical F-corona (inner zodiacal light) using a publicly released wide-field image of a total solar eclipse obtained during the Artemis II crewed lunar flyby. In this image, the solar disk is fully occulted by the Moon, providing a rare view of diffuse circumsolar emission over a wide angular extent. Although the dataset is a rendered RGB JPEG image without full photometric calibration, field stars show that the instrumental response is approximately linear in the unsaturated regime, allowing analysis of the relative morphology of the F-corona. The observed F-corona exhibits a flattened, nearly elliptical morphology aligned with the ecliptic plane, with flattening indices of 0.52-0.59 across the three color channels. The east-west intensity distribution is approximately symmetric, while a modest north-south asymmetry is present. Radial intensity profiles along ecliptic longitude and latitude are well described by power laws in solar elongation and are broadly consistent with previous observations by STEREO/HI-1A and LASCO. Comparison with the ZodiSURF zodiacal light model indicates that the observed F-corona is more extended than model predictions, particularly in the north-south direction. Within the model framework, we explore this discrepancy through an empirical, phenomenological modification of the number density distribution of the interplanetary dust. Within an empirical, phenomenological framework, a shallower radial number-density dependence with a power-law index of ~0.7 improves the match to the observed relative profiles.