天苑四
The high levels of chromospheric activity, strong magnetic field, and relatively fast rotation rate of Epsilon Eridani are characteristic of a young star. Most estimates of the age of Epsilon Eridani place it in the range from 200 million to 800 million years. The low abundance of heavy elements in the chromosphere of Epsilon Eridani usually indicates an older star, because the interstellar medium (out of which stars form) is steadily enriched by heavier elements produced by older generations of stars. This anomaly might be caused by a diffusion process that has transported some of the heavier elements out of the photosphere and into a region below Epsilon Eridani's convection zone.