We have carried out an analysis of about 160 eclipse timings spanning over 30 years of the Hyades eclipsing binary V471 Tauri that shows a long-term quasi-sinusoidal modulation of its observed eclipse arrival times .
The O–Cs have been analyzed for the “ light-time ” effect that arises from the gravitational influence of a tertiary companion .
The presence of a third body causes the relative distance of the eclipsing pair to the Earth to change as it orbits the barycenter of the triple system .
The result of the analysis of the eclipse times yields a light-time semi-amplitude of 137.2 \pm 12.0 s , an orbital period of P _ { 3 } = 30.5 \pm 1.6 yr and an eccentricity of e _ { 3 } = 0.31 \pm 0.04 .
The mass of the tertiary component is M _ { 3 } \sin i _ { 3 } \simeq 0.0393 \pm 0.0038 M _ { \odot } when a total mass of 1.61 \pm 0.06 M _ { \odot } for V471 Tau is adopted .
For orbital inclinations i _ { 3 } \gtrsim 35 ° , the mass of the third body would be below the stable hydrogen burning limit of M \approx 0.07 M _ { \odot } and it thus would be a brown dwarf .
In the next several years ( near maximum elongation ) , it should be feasible to obtain IR images and spectra of V471 Tau C that , when combined with the known mass , age , distance , and [ Fe / H ] , will serve as a benchmark for understanding the physical properties and evolution of brown dwarfs .