Tags: Star.
Pi1 Gruis is a star in the constellation Grus. It is a semi-regular red giant of spectral type S5 ranging from apparent magnitude 5.31 to 7.01 over a period of 191 days and is around 532 light-years from Earth. It is one of the brightest stars of a class of stars known as S Stars and has a companion star of apparent magnitude 10.9 that is sunlike in properties—a yellow main sequence star of spectral type G0V. Separated by 2.71′′ the pair make up a likely binary system.