Epsilon Eridani facts for kids

Epsilon Eridani (ε Eri, ε Eridani) is a star in the southern constellation Eridanus, just south of the celestial equator. It can be seen from most of Earth's surface.

It is 10.5 light years (ly) away, and has an apparent magnitude of 3.73. It is the third closest individual star or star system visible to the unaided eye.

Epsilon Eridani was the closest star known to host a planet until the unconfirmed discovery of Alpha Centauri Bb. Its age is less than a billion years. Because of its youth, Epsilon Eridani has a more active magnetic field than the present-day Sun. Its stellar wind is 30 times as strong. Its rotation period is 11.2 days at the equator. The star is smaller and less massive than the Sun, and has a lower level of metal elements. It is a main-sequence star of spectral class K2, which means that energy generated at the core through nuclear fusion of hydrogen is emitted from the surface at a temperature of about 5,000 K, giving it an orange hue.

Its planet, Epsilon Eridani b, was announced in 2000. The planet orbits in about 7 years. It is about 3.4 astronomical units (AU) away from its star.

The system includes two belts of rocky asteroids: one at about 3 AU and a second at about 20 AU, whose structure may be maintained by a hypothetical second planet, Epsilon Eridani c. Epsilon Eridani has an extensive outer debris disk of remnant planetesimals left over from the system's formation.

Epsilon Eridani may be a member of the Ursa Major Moving Group of stars that share a similar motion through the Milky Way. This suggests they share a common origin in an open star cluster. Its nearest neighbor, the binary star system Luyten 726-8, will have a close encounter with Epsilon Eridani in about 31,500 years when they will be separated by about 0.93 ly.

Epsilon Eridani has been the target of SETI searches. Epsilon Eridani appears in science fiction stories and has been suggested as a destination for interstellar travel.

Images for kids

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  Above, the northern section of the Eridanus constellation is delineated in green, while Orion is shown in blue. Below, an enlarged view of the region in the white box shows the location of Epsilon Eridani at the intersection of the two lines.

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  Illustration of the relative sizes of Epsilon Eridani (left) and the Sun (right)

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  A light curve for Epsilon Eridani, showing averages of the b and y band magnitudes between 2014 and 2021. The inset shows the periodic variation over a 12.3-day rotational period.

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  Artist's impression, showing two asteroid belts and a planet orbiting Epsilon Eridani

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  Artist's impression of the unconfirmed second planet as seen from a hypothetical moon. The distant Epsilon Eridani is visible on the left, surrounded by a faint disk of dust particles.

See also

In Spanish: Épsilon Eridani para niños