This day in space historyPlanets
On October 6, 1995, astronomers Michel Mayor and Didier Queloz announced 51 Pegasi b, the first planet found orbiting a star like our Sun. The star lies about 50 light-years away in the constellation Pegasus.
The planet is a gas giant with about half the mass of Jupiter, yet it circles its star in only 4.2 days. Mercury needs 88 days to orbit the Sun. Planets in orbits this tight became known as hot Jupiters, and few astronomers had expected them to exist. The discovery came from measuring the star’s tiny wobble as the planet tugged on it. Astronomers have since confirmed more than 6,000 exoplanets.
4.2 days
51 Pegasi b's orbital period