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Astronomers Find 3rd Planet Orbiting Closest Star to Earth
A study published in Astrophysics & Astronomy just announced the existence of a third planet orbiting the closest star to Earth. This new rocky exoplanet, Proxima d, is located in the habitable zone of its star.
The 3-star system known as Alpha Centauri hosts the closest star to Earth other than the Sun, Proxima Centauri. In August of 2016, the first exoplanet orbiting Proxima Centauri was discovered, and in January 2020, a second was found. In this February 2022 study, astronomers announced the discovery of a 3rd exoplanet orbiting Proxima Centauri.
Proxima d is the third exoplanet in its system, orbiting extremely close to its star, at only one-tenth the distance of Mercury from our Sun. Proxima d completes an orbit every 5 days and is a rocky planet around one-fourth the mass of Earth. Despite its close orbit, Proxima d is still in the habitable zone of its star, as Proxima Centauri is a red dwarf with only 12% of the Sun’s mass and 14% of its diameter.
Proxima d’s sibling planets, Proxima b and c, are also rocky planets. Proxima b, discovered in 2016, is roughly the same mass as Earth. It has an orbit of 11.2 days, at only 5% of Earth’s distance from the Sun, Proxima b is also in the habitable zone of Proxima Centauri. Meanwhile, Proxima c orbits the furthest away with a 5.2-year orbit…
