Reasons for the Slow Apsidal Rotation of the Massive Eclipsing Star V1141 Cas

High-precision photometric measurements of the unexplored eclipsing star V1141 Cas (P = 6.909^d, \(V{{ = 12.02}^{m}}\), \(e = 0.37\), Sp B1 V) have shown that the apsidal rotation velocity, \({{\dot {\omega }}_{{{\text{obs}}}}} = 0.127^\circ \)/yr, is two times slower than the theoretical value under the synchronism condition, \({{\dot {\omega }}_{{{\text{theor}}}}} = 0.235^\circ \)/yr. The physical parameters of the component stars were obtained: \({{T}_{1}} = 23\,500 \pm 400\) K, \({{M}_{1}} = 8.4 \pm 0.5{\kern 1pt} {{M}_{ \odot }}\), \({{R}_{1}} = 4.24 \pm 0.08{\kern 1pt} {{R}_{ \odot }}\), \({{T}_{2}} = 22\,000 \pm 400\) K, \({{M}_{2}} = 7.0 \pm 0.5{\kern 1pt} {{M}_{ \odot }}\), and \({{R}_{2}} = 3.38 \pm 0.08{\kern 1pt} {{R}_{ \odot }}\). The age of the system is determined to   be 7.5 million years with a solar chemical composition. The measured photometric parallax, \(\pi =0.00031^{\prime\prime} \pm 0.00004^{\prime\prime} \), is very close to the Gaia value. The interstellar extinction, \({{A}_{{\text{V}}}} = {{2.2}^{m}}\), is 40 percent higher than the survey’s data.