Epsilon Eridani facts for kids

Epsilon Eridani (also called ε Eri) is a star found in the southern part of the Eridanus constellation. You can see it from most places on Earth. It's quite close to us, about 10.5 light years away. This makes it the third closest star or star system you can see without a telescope.

Epsilon Eridani is younger than our Sun, less than a billion years old. Because it's so young, it has a very active magnetic field. Its "stellar wind" (a flow of particles from the star) is 30 times stronger than the Sun's. The star spins quite fast, completing a rotation in about 11.2 days. Epsilon Eridani is smaller and weighs less than the Sun. It also has fewer "metal" elements, which in astronomy means elements heavier than hydrogen and helium.

This star is a main-sequence star of a type called K2. This means it creates energy by joining hydrogen atoms together in its core. Its surface temperature is about 5,000 K, which gives it an orange color.

The Planet Epsilon Eridani b

In the year 2000, scientists announced they had found a planet orbiting Epsilon Eridani. This planet is named Epsilon Eridani b. It takes about 7 years for Epsilon Eridani b to complete one orbit around its star. It is about 3.4 astronomical units (AU) away from Epsilon Eridani. An AU is the distance from the Earth to the Sun.

Asteroid Belts and Debris Disk

The Epsilon Eridani system has two belts made of rocky asteroids. One belt is about 3 AU from the star, and the second is further out, at about 20 AU. Scientists think a possible second planet, Epsilon Eridani c, might help keep the second asteroid belt in place.

Beyond these asteroid belts, Epsilon Eridani has a large outer disk of leftover space material. This "debris disk" is made of small pieces of rock and dust. These pieces are what's left from when the star system first formed.

Epsilon Eridani's Neighbors

Epsilon Eridani might be part of a group of stars called the Ursa Major Moving Group. These stars all move in a similar way through the Milky Way galaxy. This suggests they might have all formed together in the same star cluster.

In about 31,500 years, Epsilon Eridani will have a close encounter with its nearest neighbor, a two-star system called Luyten 726-8. At that time, they will be about 0.93 light-years apart.

Searching for Life and Science Fiction

Because Epsilon Eridani is relatively close and has a planet, it has been a target for SETI searches. SETI is a project that looks for signs of intelligent life beyond Earth.

Epsilon Eridani has also appeared in many science fiction stories. People have even suggested it as a possible place to visit for interstellar travel, which means traveling between stars.

Images for kids

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  This picture shows where Epsilon Eridani is in the sky. The green lines show the Eridanus constellation, and Orion is in blue. The white box zooms in to show Epsilon Eridani.

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  This image compares the size of Epsilon Eridani (on the left) to our Sun (on the right). Epsilon Eridani is smaller than the Sun.

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  This graph shows how bright Epsilon Eridani appeared between 2014 and 2021. The smaller graph inside shows how its brightness changes as it spins over 12.3 days.

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  This is an artist's drawing showing the two asteroid belts and a planet orbiting Epsilon Eridani.

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  This is an artist's idea of what the unconfirmed second planet, Epsilon Eridani c, might look like from one of its moons. You can see Epsilon Eridani in the distance.

See also

In Spanish: Épsilon Eridani para niños