Epsilon Eridani
Epsilon Eridani (蔚 Eri, 蔚 Eridani) is a star in the constellation Eridanus. At a distance of 10.5 light years (ly), it has an apparent magnitude of 3.73. It is the third closest of the individual stars or star systems visible to the naked eye and is the closest star known to host an orbiting planet. Its age is estimated at less than a billion years. Because of its youth, Epsilon Eridani has a higher level of magnetic activity than the present-day Sun, with a stellar wind 30 times as strong. Its rotation period is a relatively rapid 11.2 days at the equator. Epsilon Eridani is both smaller and less massive than the Sun, and has a comparatively lower level of the elements heavier than helium. Astronomers categorize it as a main-sequence star of spectral class K2, which means the energy being generated at the core through nuclear fusion of hydrogen is emitted from the surface at a temperature of about 5000 K, giving the star an orange hue. The motion of this star along the line of sight to the Earth, its radial velocity, has been regularly observed for more than twenty years. Periodic changes in this data yield evidence of a giant planet orbiting Epsilon Eridani, making it the nearest extrasolar system with a candidate exoplanet. This object, Epsilon Eridani b, was formally announced in 2000 by a team of astronomers led by Artie Hatzes. Current data indicate that this planet orbits with a period of about 7 years at a mean separation of 3.4 astronomical units (AU <b>...</b>
EPSILON ERIDANI SOLAR SYSTEM EARTH MOON SUN VENUS JUPITER NEPTUNE SATURN MERCURY MARS URANUS PLUTO COMET HALLEY HONDA ELENIN UNIVERSE COSMOS SPACE STARS GALAXY MILKY WAY STELLAR ALPHA CENTAURI groomlake 51
