Solar twin gives glimpse into Sun’s future

Science News : In 2006, a search began for solar twins—stars that are similar to the Sun in mass, temperature, and chemical composition. Iván Ramírez of the University of Texas at Austin and his colleagues have found the closest match yet. Located just 250 light-years away and designated HIP 102152, the star is 97% as massive as the Sun, is 54 °C cooler, and has similar concentrations of more than 20 elements. The biggest difference is that HIP 102152 is 4 billion years older than the Sun—almost twice as old—making it the oldest known solar twin and a potential model of how the Sun will age. One interesting characteristic of the Sun is that it has a lower concentration of lithium than most other stars. While HIP 102152 has an even lower lithium concentration than the Sun, a previously discovered younger solar twin has a higher concentration. That finding suggests that Sun-like stars burn through their lithium as they age. Ramírez and his colleagues are now examining the star to determine if any planets orbit it.