Speaker
Description
Our Moon possesses a tenuous, collisionless "atmosphere", known as an "exosphere". In 1988, sodium was detected in the lunar exosphere through ground-based spectroscopic observations (Potter & Morgan, 1988). Due to solar radiation pressure acceleration, the sodium exosphere extends into a tail. When viewed in an Earth-centered coordinate frame, it exhibits a projected sodium spot with an angular size of approximately 3° × 3° in the anti-sunward direction (Smith et al., 1999). This feature has been observed using all-sky cameras (Matta et al., 2019; Baumgardner et al., 2021), highlighting the role of radiation pressure and surface interactions in shaping its distribution.
We have conducted observations of the lunar sodium spot at Lulin Observatory to explore the lunar sodium exosphere based on our own dataset and to provide constraints for exospheric models. A series of observations was obtained during new moon phases, enabling investigation of possible variations in the spatial distribution of the sodium spot and its temporal variability. In addition, the sodium spot would be mapped to the extended sodium tail to distinguish the contributions from different sodium release mechanisms. In this study, we characterized the spatial distribution and morphological features of the sodium emissions, and further probed the surface processes of airless bodies.
| Participate the oral/poster presentation award competition | Yes |
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