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We have obtained high-resolution spectra of four eclipsing binary systems (FMLeo, NN Del, V963 Cen and AI Phe) with the view to gaining insight into therelative orientation of their stellar spin axes and orbital axes. The so calledRossiter-McLaughlin (RM) effect, i.e. the fact that the broadening and theamount of blue- or redshift in the spectra during an eclipse depend on the tiltof the spin axis of the background star, has the potential of reconcilingobservations and theoretical models if such a tilt is found. We analyse the RMeffect by disentangling the spectra, removing the front component and measuringthe remaining, distorted lines with a broadening function (BF) obtained fromsingle value decomposition (SVD), weighting by the intensity centre of the BFin the eclipse. All but one of our objects show no significant misalignment,suggesting that aligned systems are dominant. We provide stellar as well asorbital parameters for our systems. With five measured spin-orbit angles wesignificantly increase (from 9 to 14) the number of stars for which it has beenmeasured. The spin-orbit angle $\beta$ calculated for AI Phe's secondarycomponent shows a misalignment of 87$\pm$17 degrees. NN Del, with a largeseparation of components and a long dynamical timescale for circularisation andsynchronisation, is an example of a close to primordial spin-orbit anglemeasurement.

Tracking the spin axes orbital alignment in selected binary systems - Torun Rossiter-McLaughlin effect survey