3I/ATLAS is the third-ever interstellar object discovered.
When astronomers first discovered exoplanets, they found massive ones orbiting large stars. The technology to detect smaller planets around low-mass, dim red dwarfs took time to develop. By the mid-2000s, HARPS (High Accuracy Radial velocity Planet Searcher) was specifically targeting M dwarfs and in 2009 discovered the least massive exoplanet at the time.