HD 197027 (HIP 102152) is a star in the constellation Capricornus. It has an apparent magnitude of 9.15, making it readily visible through a telescope but not to the naked eye. The object is located at a distance of 255 light years but is approaching the Solar System with a heliocentric radial velocity of .
HD 197027 has a stellar classification of G3 V, indicating that it is an ordinary G-type main-sequence star like the Sun. It has only 97% the mass of the Sun but 108% of its radius. It shines at 119% the luminosity of the Sun from its photosphere at an effective temperature of 5,718 K, similar to the Sun's 5,778 K. HD 197027's metallicity – elements heavier than helium – is similar to the Sun. At an older age of 6.92 billion years, it spins with a projected rotational velocity of about .
Since its measured properties of this star are very similar to those of the Sun, it has been considered a candidate older solar twin."The life cycle of a Sun-like star (annotated)". European Southern Observatory 28 August 2013. The abundances of 21 elements overall are more similar to the Sun than any other known solar twin. Its Iron Abundance is −0.03 with an error value of 0.02 Fe/H. (The value comes from the Hipparcos Extended Catalog.)
References
External links Oldest Solar Twin Identified HIGH PRECISION ABUNDANCES OF THE OLD SOLAR TWIN HIP 102152: INSIGHTS ON LI DEPLETION FROM THE OLDEST SUN Oldest Solar Twin Identified