GRL (2025) https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2024GL111745

Aadarsh Raj Sharma, Lot Ram, Harshaa Suhaag, Dipjyoti Patgiri, Lauriane Soret, Jean-Claude Gérard, Ian R. Thomas, Ann Carine Vandaele, Sumanta Sarkhel

We report, for the first time, the impact of interplanetary coronal mass ejections (ICME) on the recently discovered O(1S) 557.7 nm dayglow emission in the Martian atmosphere. While there are a few studies on the seasonal variation of 557.7 nm dayglow emission available in the literature, the impact of ICME has not been investigated so far. Using the instruments aboard the ExoMars-TGO and Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft, we show that the primary emission peak (75–80 km) remains unaffected during ICME events compared to quiet-times. However, an enhancement has been observed in the brightness of the secondary emission peak (110–120 km) and the upper altitude region (140–180 km). The enhancement is attributed to the increased solar electrons, X-ray fluxes and Solar Energetic Particles, augmenting the electron-impact processes causing the enhancement in the brightness. Thus, this study has an implication to the brightness of Martian upper atmosphere during intense solar transients like ICME.

Radiance limb profile of 557.7 nm emission during event-time (red), quiet-time (blue), and average-quiet-time (gray). Gray zone is 1σ variability. Red and blue horizontal bars are 10% error in the brightness.