Context : We investigate star formation in translucent , high-latitude clouds . Aims : Our aim is to understand the star-formation history and rate in the solar neighbourhood . Methods : We used spectroscopic observations of newly found candidate H \alpha emission-line stars to establish their pre-main-sequence nature . The environment was studied through molecular line observations of the cloud ( MBM 18/LDN 1569 ) in which the stars are presumably embedded . Results : Ten candidate H \alpha emission-line stars were found in an objective grism survey of a \sim 1 square degree region in MBM 18 , of which seven have been observed spectroscopically in this study . Four of these have weak ( \mid W ( H \alpha ) \mid \la 5 Å ) H \alpha emission , and six out of seven have spectral types M1 - M4 V. One star is of type F7-G1 V , and has H \alpha in absorption . The spectra of three of the M-stars may show an absorption line of LiI , although none of these is an unambiguous detection . The M-stars lie at distances between \sim 60 pc and 250 pc , while most distance determinations of MBM 18 found in the literature agree on 120 - 150 pc . For the six M-stars a good fit is obtained with pre-main-sequence isochrones indicating ages between 7.5 and 15 Myr . The mass of the molecular material , derived from the integrated ^ { 12 } CO ( 1–0 ) emission , is \sim 160 M _ { \odot } ( for a distance of 120 pc ) . This is much smaller than the virial mass ( \sim 10 ^ { 3 } M _ { \odot } ) , and the cloud is not gravitationally bound . Using a clump-finding routine , we identify 12 clumps from the CO-data , with masses between 2.2 and 22 M _ { \odot } . All clumps have a virial mass at least six times higher than their CO-mass , and thus none are in gravitational equilibrium . A similar situation is found from higher-resolution CO-observations of the northern part of the cloud . Conclusions : Considering the relative weakness or absence of the H \alpha emission , the absence of other emission lines , and the lack of clear LiI absorption , the targets are not T Tauri stars . With ages between 7.5 and 15 Myr they are old enough to explain the lack of lithium in their spectra . Based on the derived distances , some of the stars may lie inside the molecular cloud . From the fact that the cloud as a whole , as well as the individual clumps , are not gravitationally bound , in combination with the ages of the stars we conclude that it is not likely that ( these ) stars were formed in MBM 18 .