Mayor and Queloz Find the First Exoplanet Around a Sun-Like Star
A wobbling star four days from its planet opens the modern search for worlds beyond our own
Quick facts
- Discoverers
- Michel Mayor, Didier Queloz
- Announced
- October 1995
- Planet
- 51 Pegasi b, a hot Jupiter
- Recognition
- 2019 Nobel Prize in Physics
What happened
In October 1995, the Swiss astronomers Michel Mayor and Didier Queloz announced the first detection of a planet orbiting a star like our Sun, using the ELODIE spectrograph on a 1.9-meter telescope at the Observatoire de Haute-Provence in France. They found the planet, 51 Pegasi b, by measuring the Doppler shift in its host star's light as the star wobbled around the center of mass it shared with the orbiting planet, a technique known as the radial velocity method. The planet turned out to be a hot Jupiter, a gas giant with a surface temperature between roughly 1,000 and 1,800 degrees Fahrenheit that completes an orbit around its star in just four days, an arrangement unlike anything in our own solar system. Mayor and Queloz shared the 2019 Nobel Prize in Physics for the discovery.
Why it matters
51 Pegasi b's discovery launched the modern search for exoplanets, proving that planetary systems around ordinary, sun-like stars are detectable with existing instruments and that they can look nothing like our own solar system, since a gas giant orbiting closer to its star than Mercury orbits the Sun was not something theory had anticipated. The radial velocity technique Mayor and Queloz used, along with later transit-based methods, has since found thousands of confirmed exoplanets.
How we know
Mayor and Queloz's discovery was published as a peer-reviewed scientific paper and the planet has been independently confirmed by other observatories using the same radial velocity method and, in later years, additional detection techniques.
Sources
- NASA Science. Nobel Winners Changed Our Understanding with Exoplanet Discovery · Reputable sourcescience.nasa.gov · The domain "science.nasa.gov" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- NASA Science. 51 Pegasi b · Reputable sourcescience.nasa.gov · The domain "science.nasa.gov" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
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