Recent spectroscopic observations of stellar flares and possible stellar mass ejections

Investigations using data from NASA's GOLD (Global-scale Observations of the Limb and Disk) mission, have made remarkable discoveries about the Equatorial Ionization Anomaly (EIA) and Equatorial Plasma Bubbles (EPBs) in the nightside ionosphere. These findings not only challenge what we know but also introduce intriguing new questions. From its position in a geostationary orbit, the GOLD imager has captured systematic variations in EIA crests across different longitudes and seasons. Most notable, is the observation of EIA crests merging to form a ‘X’ pattern. It has also observed contrast in EPBs shapes, C-shaped and reversed C-shaped, coexisting within 6 degrees longitudinal range during calm geomagnetic conditions. The change in EPB shapes suggests the presence of large changes in the neutral wind at small spatial scales. Additionally, GOLD has revealed the intriguing pattern of multiple EPBs emerging in a regular, small-scale, periodic manner, prompting questions about the underlying mechanisms. GOLD has also recorded EPBs exhibiting large westward tilts at mid-latitudes during geomagnetic disturbance periods. Most notably, GOLD observed the EIA crest merging with the aurora during the super geomagnetic storm on 10-11 May 2024. While some of these phenomena can be explained with current knowledge and available measurements, there are observations that remain challenging to interpret. This presentation will explore these groundbreaking discoveries, offering insights into potential formation mechanisms and variabilities based on existing observations and scientific understanding.