We are entering the era in which observations of protoplanetary discs properties can indirectly probe the presence of massive planets or low mass stellar companions interacting with the disc .
In particular , the detection of warped discs can provide important clues to the properties of the star-disc system .
In this paper we show how observations of warped discs can be used to infer the dynamical properties of the systems .
We concentrate on circumbinary discs , where the mass of the secondary can be planetary .
First , we provide some simple relations that link the amplitude of the warp in the linear regime to the parameters of the system .
Secondly , we apply our method to the case of TW Hya , a transition disc for which a warp has been proposed based on spectroscopic observations .
Assuming values for the disc and stellar parameters from observations , we conclude that , in order for a warp induced by a planetary companion to be detectable , the planet mass should be large ( M _ { p } \approx 10 - 14 M _ { J } ) and the disc should be viscous ( \alpha \approx 0.15 - 0.25 ) .
We also apply our model to LkCa 15 and T Cha , where a substellar companion has been detected within the central cavity of the transition discs .