Times of light minima for V410 Aur

However, the physical and orbital properties of the tertiary are unknown. We constructed (O-C) curve with 117 new eclipse times and those collected from the literature, which shows a cyclical variation with a period of 25.44(+/-1.17)yr and a projected semimajor axis of 0.0348(+/-0.0021)d while it undergoes a long-term period decrease at a rate of dP/dt=-1.58x10^-7^d/yr.

The cyclical variation is analyzed for the light-travel time effect. The minimum mass of the third body is determined as 1.39(+/-0.13)M_{sun}_ that is much larger than the inferred value (0.97M_{sun}_) of spectroscopic investigation, which indicates that the spectroscopically tertiary is a single-lined spectroscopic binary with an unseen component. The maximum orbital semimajor axis 6.19(+/-0.67)au of the third body is determined.