OO Dra is a short-period Algol system with a \delta Sct-like pulsator .
We obtained time-series spectra between 2016 February and May to derive the fundamental parameters of the binary star and to study its evolutionary scenario .
The radial velocity ( RV ) curves for both components were presented , and the effective temperature of the hotter and more massive primary was determined to be T _ { eff, 1 } = 8260 \pm 210 K by comparing the disentangling spectrum and the Kurucz models .
Our RV measurements were solved with the BV light curves of Zhang et al .
( 2014 ) using the Wilson-Devinney binary code .
The absolute dimensions of each component are determined as follows : M _ { 1 } = 2.03 \pm 0.06 M _ { \odot } , M _ { 2 } = 0.19 \pm 0.01 M _ { \odot } , R _ { 1 } = 2.08 \pm 0.03 R _ { \odot } , R _ { 2 } = 1.20 \pm 0.02 R _ { \odot } , L _ { 1 } = 18 \pm 2 L _ { \odot } , and L _ { 2 } = 2.0 \pm 0.2 L _ { \odot } .
Comparison with stellar evolution models indicated that the primary star resides inside the \delta Sct instability strip on the main sequence , while the cool secondary component is noticeably overluminous and oversized .
We demonstrated that OO Dra is an oscillating post-mass transfer R CMa-type binary ; the originally more massive star became the low-mass secondary component through mass loss caused by stellar wind and mass transfer , and the gainer became the pulsating primary as the result of mass accretion .
The R CMa stars , such as OO Dra , are thought to have formed by non-conservative binary evolution and ultimately to evolve into EL CVn stars .