eksoplanet

An eksoplanet, or exoplanet, is a planet that orbits a star other than the Sun. Exoplanets are studied to understand planetary formation, diversity, and the potential for life beyond the Solar System. As of recent years, thousands of exoplanets have been confirmed. The first confirmed exoplanets were found in the 1990s: planets orbiting the pulsar PSR B1257+12 in 1992, and the first around a main-sequence star, 51 Pegasi b, in 1995. Since then, detection methods have advanced rapidly.

Most exoplanets are detected indirectly. The transit method observes periodic dips in starlight when a planet crosses its disk. Radial velocity measures stellar wobble due to gravity. Other approaches include direct imaging, gravitational microlensing, astrometry, and timing variations. Space missions such as Kepler and TESS have expanded the census.

Exoplanets vary from rocky Earth-sized bodies to gas giants larger than Jupiter. They orbit at diverse distances, yielding a broad range of temperatures. Some are hot Jupiters orbiting close to their stars; many reside in temperate zones where atmospheres and surface conditions could support liquid water, depending on composition.

Atmospheric studies via spectroscopy during transits or direct imaging are active fields. While atmospheric composition and possible biomarkers are investigated, no definitive signs of life have been detected.

Exoplanet discoveries are cataloged by databases such as NASA's Exoplanet Archive and the Extrasolar Planets Encyclopaedia, which provide parameters and enable statistical studies of planet populations.