Stellar Space Weather Broadens Narrowband Technosignatures: Implications for SETI Searches

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Researchers at the SETI Institute, led by Vishal Gajjar and Grayce C. Brown, warn that stellar space weather can broaden ultra-narrow radio signals as they travel, so a perfect spike may smear in frequency; they calibrate this broadening with solar-system data to estimate how much it widens across stars and observing frequencies, especially around active M-dwarfs, meaning searches should look for broadened signals rather than razor-thin lines.