Washington: Astronomers have identified a star, HIP 102152, which resembles our Sun more than any other solar twin - except that it is about four billion years older.
This older, but almost identical, twin has given the astronomers an unprecedented chance to see how the Sun will look when it ages and the new observations are also going to provide an important first clear link between a star`s age and its lithium content, and in addition suggest that HIP 102152 may be host to rocky terrestrial planets.
Jorge Melendez (Universidade de Sao Paulo, Brazil), the leader of the team and co-author of the new paper explained that for decades, astronomers have been searching for solar twins in order to know our own life-giving Sun better.
He said that but very few have been found since the first one was discovered in 1997 and 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.
The team studied two solar twins - one that was thought to be younger than the Sun (18 Scorpii) and one that was expected to be older (HIP 102152).
They used the UVES spectrograph on the Very Large Telescope (VLT) at ESO`s Paranal Observatory to split up the light into its component colors so that the chemical composition and other properties of these stars could be studied in great detail.
They found that HIP 102152 in the constellation of Capricornus (The Sea Goat) is the oldest solar twin known to date and is estimated to be 8.2 billion years old, compared to 4.6 billion years for our own Sun. On the other hand 18 Scorpii was confirmed to be younger than the Sun-about 2.9 billion years old.
Studying the ancient solar twin HIP 102152 allows scientists to predict what may happen to our own Sun when it reaches that age, and they have already made one significant discovery.
The results have been published in Astrophysical Journal Letters.