Geometry of Sun and RX J0439.8−6809 in the Galaxy shown schematically. Panel a): view from above the Milky Way plane. Panel b): decomposition of the space velocity in the Milky Way into the components v_rot, the velocity parallel to the disk in the direction of circular rotation, v_axis, the velocity component pointing (parallel to the disk) at the rotation axis of the Galaxy, and v_z, the velocity perpendicular to the disk; the outward direction has a positive sign. Panel c): the geometry as seen from the Milky Way rotation axis. Velocities are given in GSR (see Sect. 4.1). The radial velocity of the star is +220 km s^-1 (Werner & Rauch 2015).