Apsidal Motion and Photometric Elements of the Eccentric Eclipsing Binary V401 Lacertae

New UBV photometric observations of the recently discovered eccentric orbit binary V401 Lacertae were analyzed by using the Wilson-Devinney program. Seven new minimum times were estimated by using new observations. The analysis of the light curves and all available minimum times has revealed that the system is detached, with the orbital eccentricity $e = 0.1734 \pm 0.0003$ , the longitude of the periastron $\omega = {63\rlap {.}{}^{\mathrm {\circ }}93} \pm {0\rlap {.}{}^{\mathrm {\circ }}15}$ , the rate of change of the longitude of periastron $\dot{\omega} = {0\rlap {.}{}^{\mathrm {\circ }}0200} \pm {0\rlap {.}{}^{\mathrm {\circ }}0024} \;\mathrm{cycle}^{-1}$ , corresponding to an apsidal motion period of $U = 96.2 \pm 11.4 \,\mathrm{yr}$ . The apsidal motion of the system has been confirmed by the significant difference on the longitude of periastron ( $\omega$ ) obtained from two light curves (Hipparcos and ourselves) in two different epochs.