In a landmark discovery on November 1, 1995, Michel Mayor and Didier Queloz found the first planet orbiting a sunlike star, 51 Pegasi b (Dimidium), at Haute-Provence Observatory, a turning point for exoplanet science.

Since then, exoplanet research has exploded, revealing thousands of worlds with diverse types—from hot Jupiters to super-Earths and water-rich or desert planets—though no confirmed life-harboring planet has been found yet.

Mayor and Queloz shared the 2019 Nobel Prize in Physics for their Dimidium work, alongside James Peebles for cosmology.

Dimidium is a hot Jupiter—larger in diameter than Jupiter but about half its mass—orbiting 51 Pegasi at roughly 5 million miles away with a 4.2-day orbital period.

The discovery relied on measuring the star's wobble via Doppler shifts and light analysis, and it quickly spurred verification and a surge in exoplanet research, including the first direct image of an exoplanet in 2004.