... Planets . ... Exoplanets . ... Image 1-Artists impression of an exoplanet in orbit around host star. ... Supposedly the closest exoplanet to us is also located in this system around one of the other stars, Alpha Centauri B. €аThis hot, Earth-sized, rocky exoplanet, Alpha Centauri Bb was discovered by astronomers in Geneva last year. ... The exoplanet, 55 Cancri e has almost 8 times the mass of the Earth with a diameter twice the size and is thought to be a carbon planet. ... Exoplanets Glossary | ...