The sun has a twin in the left claw of Scorpio.
The solar twin is 18 Scorpii, located in the constellation Scorpio the Scorpion, a mere 46 light-years from Earth. A light-year is about 6 trillion miles (10 trillion kilometers), the distance light travels in a year. In cosmic terms, this is quite close by.
Astronomers have looked for sunlike stars for years, because stars similar to our sun might have orbiting planets like Earth, and might be good places to search for signs of extraterrestrial life.
They have trained their sights on 18 Scorpii in particular since 1997, when scientists identified it as a potential solar twin. On Tuesday, a team of astronomers from Villanova University in Pennsylvania noted just how much the two stars have in common.
They are both about the same age, between 4 billion and 5 billion years old. They have about the same mass, the same radius and the same surface temperature. They take approximately the same amount of time to rotate — somewhere around 25 days. They have similar cycles of activity, sunspots in the sun's case.
Villanova's Edward Guinan said there is a certain sport to finding the closest stellar match to the sun, but there is scientific value as well. Finding a likely twin of the sun shows that the sun is likely a normal star, Guinan said at a meeting of the American Astronomical Society in Atlanta.