Interstellar Extinction at High Galactic Latitudes: An Analytical Approximation
Distance dependences of interstellar extinction AV(d) for a number of high-latitude areas of the southern sky were obtained using the data of the RAVE DR6 spectroscopic survey and the Gaia DR2/EDR3 astrometric survey. These dependencies were approximated by the classical barometric function (cosecant law). Function parameters were then approximated by spherical functions. The resulting analytical 3D model of interstellar extinction AV can be used to estimate the values of AGal for the stars in the Galaxy with known parallaxes, as well as the total (galactic) extinction values in a given direction.