<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "On the Stäckel potential approximation in the extended solar neighbourhood"^^ . "The problem of the third integral of motion has been studied for decades. Its existence was determined at the beginning of numerical experiments with orbits in an axisymmetric potential and by observations\r\nof triaxiality in the velocity dispersion of nearby stars. In general it is not possible to derive an exact\r\nexpression for a general axisymmetric potential analytically. One way to find an exact third integral of\r\nmotion is to approximate the gravitational potential with a potential of the Stäckel form. In addition to\r\nthe third integral of motion, another important property of the Stäckel potential is that it separates the\r\nHamilton-Jacobi equation in confocal spheroidal coordinates. This results in an alignment of the velocity\r\nellipsoid with the spheroidal coordinate system in the meridional plane. In this thesis we construct a\r\nStäckel model, fixing the focal point of these coordinates based on recent observations of the velocity\r\nellipsoid (Binney et al. 2014a).\r\nThe aim of this PhD thesis is to show how a universal Stäckel potential works. This Stäckel model\r\nis focused on the region of the extended solar neighbourhood, up to 2 kpc radius around the Sun. The\r\nfree parameters are constrained with the observational values of the local volume and surface density.\r\nStudying the vertical structure we can predict the behaviour of the local vertical force and radial dependencies\r\nat 1.1 kpc far from the plane. The value of the focal point is very important, because for different\r\nvalues we obtain different profiles for the radial density, different values for the scale length and different\r\nbehaviour for the vertical force at large heights. We derive again the orientation of the velocity ellipsoid\r\nin the meridional plane based on RAVE data. The result for the tilt angle is in agreement with Binney\r\net al. (2014a), both for the complete sample of red clump giants and also for different metallicities. This\r\nresult is a confirmation of the derived Stäckel model."^^ . "2015" . . . . . . . "Alberto"^^ . "Nardin"^^ . "Alberto Nardin"^^ . . . . . . "On the Stäckel potential approximation in the extended solar neighbourhood (PDF)"^^ . . . "thesis_nardin.pdf"^^ . . . "On the Stäckel potential approximation in the extended solar neighbourhood (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "On the Stäckel potential approximation in the extended solar neighbourhood (Other)"^^ . . . . . . "preview.jpg"^^ . . . "On the Stäckel potential approximation in the extended solar neighbourhood (Other)"^^ . . . . . . "medium.jpg"^^ . . . "On the Stäckel potential approximation in the extended solar neighbourhood (Other)"^^ . . . . . . "small.jpg"^^ . . . "On the Stäckel potential approximation in the extended solar neighbourhood (Other)"^^ . . . . . . "indexcodes.txt"^^ . . "HTML Summary of #18707 \n\nOn the Stäckel potential approximation in the extended solar neighbourhood\n\n" . "text/html" . . . "520 Astronomie"@de . "520 Astronomy and allied sciences"@en . .