Although their primary purpose is to look for exoplanets, observatories like the Kepler Space Telescope and the Transiting Exoplanet Survey Satellite (TESS) have supplied a vast amount of data on stellar flares, detected with high-precision photometry by broadband filters in the visible light spectrum.
The stars are so far away that they appear only as points of light to these telescopes, and the phenomena interpreted as stellar flares are abrupt increases in the brightness of these points.
There is also a lack of data in other parts of the electromagnetic spectrum, and most studies of these events focus on irradiated energy. Observations have detected "superflares," huge magnetic eruptions in the atmosphere of stars with energies 100 to 10,000 times greater than the most energetic solar flares. The question is whether any of the available models can explain such high levels of energy.
Two models are available. The more popular one treats the radiation of a superflare as blackbody emission at a temperature of 10,000 Kelvin. The other associates the phenomenon with a process of ionization and recombination of hydrogen atoms.
A study conducted by researchers affiliated with the Mackenzie Center for Radio Astronomy and Astrophysics (CRAAM) at Mackenzie Presbyterian University (UPM) in Brazil and the University of Glasgow's School of Physics and Astronomy in the United Kingdom analyzed the two models.
"Given the known processes of energy transfer in flares, we argue that the hydrogen recombination model is physically more plausible than the blackbody model to explain the origin of the broadband optical emission…
phys.org