ItemArticle

Non-linear solar EUV-driven sodium release from the lunar surface: a contrast to the linear PSD model

Title
Non-linear solar EUV-driven sodium release from the lunar surface: a contrast to the linear PSD model
Creator
Devaraj, A.; Narendranath, S.; Kartha, Sreeja S.; Sarantos, M.; Akhil, Krishna R.; Mathew, Blesson; Sivarani, T.; Nidhi, S.; Anbazhagan, P.; Selvakumar, G.
Description
The correlation between solar Extreme Ultra-Violet (EUV) radiation above 8.8eV and the release of sodium from the lunar surface via photon-stimulated desorption (PSD) is investigated. We use simultaneous measurements of EUV photon flux and Na optical spectral line flux (FNa) from the lunar exosphere. Data were acquired with the high-resolution (R?72000) Echelle Spectrograph on the 2.34-m Vainu Bappu Telescope during the lunar first quarter (2024 JanuaryMarch), observing NaI D2 and D1 flux at altitudes below ?590km from the surface. Simultaneous EUV and FUV measurements were acquired from the GOES-R Series Extreme Ultraviolet Sensor (EUVS), while NUV data were obtained from the Total and Spectral Solar Irradiance Sensor-1 (TSIS-1) aboard the ISS. We correlated FNa with EUV photon flux from EUVS across six bands spanning 2561405 (48.58.8eV) and NUV (20004000 from TSIS-1. A non-linear rise in lunar exospheric sodium with increasing EUV and FUV fluxes was observed, contrasting with previous linear PSD models. The EUV radiation above 10eV drives sodium release, with 256-304wavelengths as dominant contributors. Additionally, the NUV flux and FNa are positively correlated, indicating the role of sodium release. The zenith column density averages 3.3 109 atoms cm-2, with Characteristic temperatures averaging at ?6700K and scale heights of ?1500km. Elevated temperatures and sodium densities during solar activity suggest enhanced Na release during flares. These results emphasize the need for a revised PSD model above 8.8 eV and improved constraints on the PSD cross-section. The Author(s) 2025. Published by Oxford University Press on behalf of Royal Astronomical Society.
Source
Monthly Notices of the Royal Astronomical Society;Volume;543;Issue;2;pp.1079-1091
Date
01-01-2025
Publisher
Oxford University Press
Subject
Moon; Planets and satellites: atmospheres; planets and satellites: surfaces; Sun: UV radiation; Techniques: spectroscopic Telescopes
Coverage
Devaraj A., Department of Physics and Electronics, CHRIST (Deemed to be University), Bengaluru, 560029, India, Aryabhatta Research Institute of Observational Sciences, Devasthal Observatory, Uttarakhand, Nainital, 263001, India; Narendranath S., Space Astronomy Group, U R Rao Satellite Centre, ISRO, Bengaluru, 560037, India; Kartha S.S., Department of Physics and Electronics, CHRIST (Deemed to be University), Bengaluru, 560029, India; Sarantos M., Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, 20771, MD, United States; Akhil K.R., Department of Physics and Electronics, CHRIST (Deemed to be University), Bengaluru, 560029, India; Mathew B., Department of Physics and Electronics, CHRIST (Deemed to be University), Bengaluru, 560029, India; Sivarani T., Indian Institute of Astrophysics, Bengaluru, 560034, India; Nidhi S., Department of Physics and Electronics, CHRIST (Deemed to be University), Bengaluru, 560029, India, The Oxford College of Science, 17th, 32, 19th Main road, Sector 4, HSR Layout, Karnataka, Bengaluru, 560102, India; Anbazhagan P., Indian Institute of Astrophysics, Bengaluru, 560034, India; Selvakumar G., Indian Institute of Astrophysics, Bengaluru, 560034, India
Rights
All Open Access; Gold Open Access; Green Open Access
Relation
ISSN: 358711; CODEN: MNRAA
Format
online
Language
English
Type
Article

Citation

Devaraj, A.; Narendranath, S.; Kartha, Sreeja S.; Sarantos, M.; Akhil, Krishna R.; Mathew, Blesson; Sivarani, T.; Nidhi, S.; Anbazhagan, P.; Selvakumar, G., “Non-linear solar EUV-driven sodium release from the lunar surface: a contrast to the linear PSD model,” CHRIST (Deemed To Be University) Institutional Repository, accessed June 18, 2026, https://archives.christuniversity.in/items/show/22815.

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