Located 250 light-years from Earth, the star HIP 102152 is the closest twin ever observed, except that it is nearly 4 billion years older than our sun, they said.
This older but almost identical twin provides an unprecedented chance to see how the sun will look when it ages, research leader Jorge Melendez of the University of Sao Paulo in Brazil said.
"For decades, astronomers have been searching for solar twins in order to know our own life-giving sun better," he said. "But very few have been found since the first one was discovered in 1997."
The astronomers used the European Southern Observatory's Very Large Telescope in the Atacama Desert in Northern Chile to study the twin.
"We have now obtained superb-quality spectra from the VLT and can scrutinize solar twins with extreme precision, to answer the question of whether the sun is special," Melendez said in an ESA release.
HIP 102152 in the constellation of Capricornus is estimated to be 8.2 billion years old, compared to 4.6 billion years for our own Sun.
The star has an unusual chemical composition pattern that is subtly different to most other solar twins but similar to the sun, the researchers said.
Both show a deficiency of the elements that are abundant in meteorites and on Earth, a strong hint HIP 102152 may host terrestrial rocky planets, they said.
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