Abinary star system of two identical stars orbiting their common centre of mass observed with the gaia satellite. the system has a parallax of 19 mas (milli-arcsecond), and each star has a flux density in gaia's b, filter at 1 = 532 nm of 5.9x10-13 erg/s/cm² / å and a flux density in gaia's r, filter at 1 = 797 nm of 4.8x10-13 erg/s/cm²/å. adaptive optics imaging observations at a large telescope resolve the two stars at many epochs, giving an orbital semi-major axis of 76 mas and a period of 6.0 years. (b) what is the distance to the stars? express your answer in pc and km.