Context : Members of nearby moving groups are promising candidates for the detection of stellar or substellar components by direct imaging .
Mass estimates and magnitude measurements of detected companions to young stars are valuable input data to facilitate the refinement of existing pre-main-sequence stellar models .
In this paper we report on our detection of a close companion to HD 160934 , a young active star , SB1 spectroscopic binary and a suggested member of the AB Doradus moving group .

Aims : We obtained high angular resolution images of nearby young stars , searching for close companions .
In the case of HD 160934 , direct imaging is combined with unresolved photometry to derive mass estimates .

Methods : High angular resolution was achieved by means of the so-called “ Lucky Imaging ” technique , allowing direct imaging close to the diffraction limit in the SDSS z ’ band .
Our results are combined with pre-discovery HST archive data , own UBV ( RI ) _ { C } broadband photometry , published JHK magnitudes and available radial velocity measurements to constrain the physical properties of the HD 160934 close binary .

Results : At an assumed age of \sim 80 Myr , we derive mass estimates of 0.69 M _ { \sun } and 0.57 M _ { \sun } , respectively , for HD 160934 and its close companion .
We suggest that the direct detection may be identical to the spectroscopically discovered companion , leading to a period estimate of \sim 8.5 years and a semimajor axis of a \approx 4.5 A.U .

Conclusions :