The contact binary V344 Lacertae: is it a triple system?

The $VRI$ passbands light curves of V344 Lac were presented and analyzed by using the latest version of the W-D code. The observed spectrum reveals that V344 Lac is not an A3 type but would be a later F type star according to the yielded temperature. The results of solution show that V344 Lac is an A-subtype contact binary, with a moderate photometric mass ratio of $0.387\pm 0.003$ and a moderate contact factor of $44.6\pm 3.0\%$. Based on the parallax given by Gaia, the parameters of the components are estimated as: $M_{1}=1.16~\mathrm{M}_{\odot }$, $M_{2}=0.45~\mathrm{M}_{\odot }$, $R_{1}=1.31~\mathrm{R}_{\odot }$, $R_{2}=0.88~\mathrm{R}_{\odot }$, $L_{1}=2.512~\mathrm{L}_{\odot }$, $L_{2}=1.057~\mathrm{L}_{\odot }$. The period investigation indicates that V344 Lac may have an eccentric orbital oscillation, with $P_{3}=12.4\pm 0.5~\text{yr}$, $A_{3}=0.0020\pm 0.0002~\text{d}$, and $e=0.38\pm 0.16$. Analysis shows such oscillation would be caused by a magnetic activity which can be explained by the Applegate mechanism. Meanwhile, according to the value of $l_{3}$ and the estimated physical parameters of V344 Lac, the mass of the third companion may be $0.79~\mathrm{M}_{\odot }$. This third body could be a wide company.