  V907 Scorpii is a unique triple system in which the inner binary component
has been reported to have switched on and off eclipses several times in modern
history. In spite of its peculiarity, observational data on this system are
surprisingly scarce. Here we make use of the recent Transiting Exoplanet Survey
Satellite observations, as well as our own photometric and spectroscopic data,
to expand the overall data set and study the V907 Sco system in more detail.
Our analysis provides both new and improved values for several of its
fundamental parameters: (i) the masses of the stars in the eclipsing binary are
2.74 +/- 0.02 M_0 and 2.56 +/- 0.02 M_0; and (ii) the third component is a
solar-type star with mass 1.06 +/-0.11 M_0 (90% C.L.), orbiting the binary on
an elongated orbit with an eccentricity of 0.47 +/- 0.02 and a period of 142.01
+/- 0.05 days. The intermittent intervals of time when eclipses of the inner
binary are switched on and off are caused by a mutual 26.2 (+/- 2.6)
inclination of the inner- and outer-orbit planes, and a favorable inclination
of about 71 deg of the total angular momentum of the system. The nodal
precession period is Pv = 63.5 +/- 3.3 yr. The inner binary will remain
eclipsing for another approx 26 yr, offering an opportunity to significantly
improve the parameters of the model. This is especially true during the next
decade when the inner-orbit inclination will increase to nearly 90 degrees.
Further spectroscopic observations are also desirable, as they can help to
improve constraints on the system's orbital architecture and its physical
parameters.
