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We investigate spherically symmetric static and dynamical Brans-Dicke theoryexact solutions using invariants and, in particular, the Newman Penroseformalism utilizing Cartan scalars. The GR limit of these solutions is examinedthrough the use of Cartan invariants via the Cartan-Karlhede algorithm and isadditionally supported by analysis of scalar polynomial invariants. It isdetermined that the appearance of horizons in these spacetimes dependsprimarily on one of the parameters, $n$, of the family of solutions. Inparticular, expansion-free surfaces appear which, for a subset of parametervalues, define additional surfaces distinct from the standard surfaces (e.g.,apparent horizons) identified in previous work. These surfaces in staticspherically symmetric Brans-Dicke solutions was previously shown to correspondto the Schwarzschild horizon in general relativity when an appropriate limitexists between the two theories. We show additionally that other geometricallydefined horizons exist for these cases, and identify all solutions for whichthe corresponding general relativity limit is not a Schwarzschild one, yetstill contains horizons. The identification of some of these other surfaces wasnoted in previous work and is characterized invariantly in this work. In thecase of the family of dynamical Brans-Dicke solutions, we identify similarinvariantly defined surfaces as in the static case and present an invariantcharacterization of their geometries. Through the analysis of the Cartaninvariants, we determine which members of these families of solutions arelocally equivalent, through the use of the Cartan-Karlhede algorithm. Inaddition, we identify black hole surfaces, naked singularities, and wormholeswith the Cartan invariants. The aim of this work is to demonstrate theusefulness of Cartan invariants for describing properties of exact solutions.

Invariant description of static and dynamical Brans-Dicke spherically symmetric models