2005AJ....130..234M

We present new spectroscopic and BVRI photometric observations of the double-lined eclipsing binary AV Del (period=3.85 days) conducted over six observing seasons. A detailed radial velocity and light-curve analysis of the optical data shows the system to be most likely semidetached, with the less massive and cooler star filling its Roche lobe. The system is probably a member of the rare class of ``cool Algol'' systems, which are distinguished from the ``classical'' Algol systems in that the mass-gaining component is also a late-type star rather than a B- or A-type star. By combining the spectroscopic and photometric analyses, we derive accurate absolute masses for the components of M₁=1.453±0.028M_☉and M₂=0.705±0.014M_☉and radii of R₁=2.632±0.030R_☉ and R₂=4.233±0.060R_☉, as well as effective temperatures of 6000±200 and 4275±150 K for the primary and secondary, respectively. There are no obvious signs of activity (spottedness) in the optical light curve of the binary.