III Simposio de Postgrado 2025: Ingeniería, ciencia e innovación

01 33 Detection of Na, K and other species in the lunar atmosphere Yogita Patel ¹* P. Rojo ¹ V. Ivanov ¹ M. Caballero ¹ *E-mail: ypatel@das.uchile.cl ¹ Department of Astronomy, University of Chile Resumen The Earth’s Moon has a tenuous, collisionless atmosphere. Its surface is continuously bombarded by energetic particles such as ions, electrons, photons, and meteoroids, which alter its chemical composition, and form regolith and a neutral gas exosphere. This project aims to detect the lunar exosphere using Earth based observations, and identify atmospheric sodium (Na), potassium (K), and other species (e.g., Ti, Ba). The primary objective is to improve current surface density upper limits for these elements, and monitor variations in Na and K caused by the Perseid meteor shower in August 2022. To this end, two additional observations were made before and after the shower peak on August 11/12. We acquired multiple spectra using the MIKE spectrograph on the Magellan Telescope at Las Campanas Observatory by mapping the edge of the moon known as the lunar limb, placing the MIKE’s slit at different positions along the Moon’s edge, such that the slit center along its length is positioned approximately 100 km (54 arcseconds) above the lunar surface, covering wavelength ranges of 3350–5000 Å (blue channel) and 4900–9500 Å (red channel) with the slit size of 0.35 x 5”. Additionally, we explore the potential of using the Moon’s surface itself as a reference for flux calibration instead of standard stars, because of its uniform reflectance property. This approach may reduce calibration errors and enhanced the accuracy of future lunar exosphere studies. __Referencias [1] A. Berezhnoi, Yu.I. Velikodsky, Yu.V. Pakhomov and C. Wöhler, Planet. Space Sci. 228, 105648 (2023) [2] A.A. Berezhnoy, K.I. Churyumov, V.V. Kleshchenok, E.A. Kozlova, V. Mangano, Yu.V. Pakhomov, V.O. Ponomarenko, V.V. Shevchenko and Yu.I. Velikodsky, Planet. Space Sci. 96, 90– 98 (2014) [3] P. Wurz, U. Rohner, J.A. Whitby, C. Kolb, H. Lammer, P. Dobnikar and J.A. Martín- Fernández, Icarus 191, 486–496 (2007)