Can solar system observations tell us something about the cosmological constant?

In this note, we show that the latest determinations of the residual perihelion advances delta omega of the inner planets of the Solar System, obtained by accounting for almost all known Newtonian and post-Newtonian orbital effects, yield only very broad constraints on the cosmological constant Lambda. Indeed, from, e.g., delta omega = -0.0036 +/- 0.0050 arcseconds per century for Mercury, one gets -2 x 10(-34) km(-2) < Lambda < 4 x 10(-35) km(-2). The currently accepted value for Lambda, obtained from many independent cosmological and large-scale measurements, amounts to almost 10(-46) km(-2).