Heliocentric distance from galactic x y and z coordinates How can I get heliocentric distance to a star when I have galactic x y and z coordinates known ?
The galactic coordinate system is centred on the sun with the xy plane in the plane of the galaxy and the x coordinate pointed towards the centre of the galaxy.

Since it is a heliocentric system the Euclidian distance is $\sqrt{x^2+y^2+z^2}$.