DN Bootis: A low mass-ratio W UMa-type contact binary

New photoelectric BVR light curves and radial velocity curves were obtained for the HIPPARCOS discovery DN Boo at the TÜBİTAK1 National Observatory of Turkey (TUG) and Dominion Astrophysical Observatory (DAO), respectively, to determine physical nature of the variable. The character of the obtained light curves and double-lined spectroscopic structures in the obtained spectra are revealed that DN Boo is a genuine EW type eclipsing binary. During the analysis of our new observations a simultaneous solution were derived for the photometric and spectroscopic data by using the Wilson–Devinney code and orbital parameters with absolute dimensions of the system were determined for the first time. Finally, the importance of very low mass-ratio contact binaries in the late stages of close binary evolution was discussed.