We present new V -band differential brightness measurements as well as new radial-velocity measurements of the detached , circular , 0.84-day period , double-lined eclipsing binary system CV Boo .
These data along with other observations from the literature are combined to derive improved absolute dimensions of the stars for the purpose of testing various aspects of theoretical modeling .
Despite complications from intrinsic variability we detect in the system , and despite the rapid rotation of the components , we are able to determine the absolute masses and radii to better than 1.3 % and 2 % , respectively .
We obtain M _ { A } = 1.032 \pm 0.013 M _ { \sun } and R _ { B } = 1.262 \pm 0.023 R _ { \sun } for the hotter , larger , and more massive primary ( star A ) , and M _ { B } = 0.968 \pm 0.012 M _ { \sun } and R _ { B } = 1.173 \pm 0.023 R _ { \sun } for the secondary .
The estimated effective temperatures are 5760 \pm 150 K and 5670 \pm 150 K. The intrinsic variability with a period \sim 1 % shorter than the orbital period is interpreted as being due to modulation by spots on one or both components .
This implies that the spotted star ( s ) must be rotating faster than the synchronous rate , which disagrees with predictions from current tidal evolution models according to which both stars should be synchronized .
We also find that the radius of the secondary is larger than expected from stellar evolution calculations by \sim 10 % , a discrepancy also seen in other ( mostly lower-mass and active ) eclipsing binaries .
We estimate the age of the system to be approximately 9 Gyr .
Both components are near the end of their main-sequence phase , and the primary may have started the shell hydrogen-burning stage .