Abstract
An analysis of TESS satellite observations of the AS Cam eclipsing binary has shown that the light of this source pulsates at two frequencies: $${{\nu }_{1}} = 0.7556$$ days–1 and $${{\nu }_{2}} = 0.8658$$ days–1 with the amplitudes $${{A}_{1}} = 0_{.}^{{\text{m}}}0110$$ and $${{A}_{2}} = 0_{.}^{{\text{m}}}0087,$$ correspondingly. Such variations are typical for slowly pulsating B-type stars. We modeled the light curves of AS Cam obtained from 1968 to 2019 to confirm the discovery of a gradual increase in the orbit eccentricity of the system by approximately 0.018 over 50 years. A third light, as one of the light curve solution parameters, on average, amounts to approximately 4% of the total luminosity of the system. For AS Cam this would correspond to an F8–F9-type suggested third body—a main sequence star, the presence of which follows from the light equation of the system. If the third light is a result of a random overlapping of a star unrelated to AS Cam, then the third body may turn out to be a degenerate object or a close binary system. The extremely slow apsidal motion in this system (compared to the value predicted by the standard theory) can be explained by the gravitational influence of a third body with a mass of about $$1.2{{M}_{ \odot }}$$ and an orbital inclination of about $$70$$ with respect to the image plane.