exoplanet

noun

1. A planet which exists outside Earth's solar system.

   “More such announcements will likely come in the months to follow, as the first space observatory dedicated to hunting exoplanets, called COROT, begins full operation and researchers complete their calculations.”

   “In the past two years, NASA’s Kepler Space Telescope has located nearly 3,000 exoplanet candidates ranging from sub-Earth-sized minions to gas giants that dwarf our own Jupiter. Their densities range from that of styrofoam to iron.”

   “In a first for astronomers studying worlds beyond our solar system, data from the Hubble Space Telescope have revealed water vapor in the atmosphere of an Earth-size planet. Although this exoplanet orbits a star that is smaller than our sun, it falls within what’s known as the star’s habitable zone, the range of orbital distances where it would be warm enough for liquid water to exist on a planet’s surface.”

   “Astronomers have used two different exoplanet-detecting satellites to solve a cosmic mystery and reveal a rare family of six planets located about 100 light-years from Earth. […] Many exoplanets have been found orbiting dwarf stars that are much cooler and smaller than our sun, such as the famed TRAPPIST-1 system and its seven planets, announced in 2017.”

   “Now a team of researchers is offering what it contends is the strongest indication yet of extraterrestrial life, not in our solar system but on a massive planet, known as K2-18b, that orbits a star 120 light-years from Earth. A repeated analysis of the exoplanet’s atmosphere suggests an abundance of a molecule that on Earth has only one known source: living organisms such as marine algae.”