The planets orbiting Iota Horologii (inset) enjoy only brief respites from their tempestuous sun. The star, located 56 light-years away in the southern constellation Horologium, boasts the shortest starspot cycle ever seen: 1.6 years. The sunspot cycle of our own sun (main image), by contrast, waxes and wanes every 11 years. When sunspot numbers peak, the sun can hurl satellite-frying flares toward Earth. So any residents of the Iota Horologii system—which bears at least one giant planet—presumably experience more frequent outbursts, astronomers will report in an upcoming issue of The Astrophysical Journal Letters. Similar conditions may have confronted Earth as life was struggling to establish itself. At that time, the sun likely resembled Iota Horologii, because the star is young: it's thought to have escaped from the Hyades star cluster, which is just 600 million years old, or about one-eighth our sun's present age.
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