Interstellar Extinction at High Galactic Latitudes: An Analytical Approximation

Abstract

Distance dependences of interstellar extinction (${{A}_V}(d)$) 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 A_V can be used to estimate the values of ${{A}_{{{Gal}}}}$ for the stars in the Galaxy with known parallaxes, as well as the total (galactic) extinction values in a given direction.