Work

Multiviewpoint Tracking of a Coronal Mass Ejection Driven Shock Propagating to Mars: Implications for Space Weather Forecasting

Year: 2026

Type: article

Abstract: We present a case study of a coronal mass ejection (CME) that was associated with in situ signatures at Mars and erupted on 2025 March 28. We estimate the time of arrival (ToA) of its associated shock at Mars, focusing on the role of remote sensing observations in improving forecast accuracy. The CME shock is tracked from the middle corona to approximately 150 R ⊙ using all available viewpoints. This CME was observed by multiple instruments on board three spacecraft, including LASCO/C2 and C3, STEREO-A/HI1A and HI2A, and SolO/SoloHI. A semiautomatic, minimization-based fitting technique, adapted to work with heliospheric imager data for the first time, is employed to reconstruct the 3D shock geometry and to quantify event-specific fitting uncertainties. These reconstructions are then used as input to a data-driven two-phase kinematics model to predict the ToA at Mars. Predictions are validated using in situ measurements from the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. By including heliospheric imager data in our analysis, we are able to determine the shock arrival at Mars within 3.1 hr of the observed shock in MAVEN. We also test different combinations of remote sensing datasets to assess how data coverage influences arrival-time estimates. We find that in this case observations from heliospheric imagers at larger heliocentric distances are essential for capturing the CME deceleration and avoiding early-arrival predictions. Finally, we highlight the importance of realistic, event-specific uncertainty estimates for space weather forecasting at multiple locations, particularly in the context of ongoing space exploration and future human missions.

Source: The Astrophysical Journal

DOI: 10.3847/1538-4357/aea13e