If you have read my previous articles on Starbade.com, you might have noticed that I write a lot about exoplanets. Those exoplanets can range through oddly formed worlds through deadly planets that have over 1000 mph winds. New exoplanets are being discovered quicker and quicker, but have you ever wondered what the first exoplanet ever discovered was?
On October 6th, 1995, at the Haute-Provence Observatory, two Swiss astronomers discovered a gravitational pull in the constellation of Pegasus that ended up being a planet 50 light-years away from Earth! This discovery has also helped create an entirely new range of astronomical discovery. The planet was named 51 Pegasi b, but the International Astronomical Union calls it Dimidium which means half in Latin because it has half of the mass of Jupiter. Either way, 51 Pegasi b was the first confirmed exoplanet ever discovered.
51 Pegasi b was the first exoplanet discovered orbiting a Sun-like star. The planet was discovered using Radial Velocity and takes 4 days to orbit its star. It is a hot Jupiter with temperatures of 1,000-1,800 degrees F. The planet is tidally locked which means it doesn’t rotate.
The topic of 51 Pegasi b being the first planet discovered is debated. Some say PSR B1257+12 (Discovered in January 22, 1992) is the first exoplanet to be discovered, but at the time people thought it was strange that this planet was orbiting a pulsar star so they didn’t count it as a planet. Errai (announced in July 1988) was another exoplanet discovered 6 years before 51 Pegasi b, but it was confirmed late. Either way, there are currently over 5,000 exoplanets discovered, these were the first ones.
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