We have identified seven independent pulsation modes in the helium-atmosphere variable ( DBV ) white dwarf star CBS 114 , based on 65 hours of time-resolved CCD photometry from the 0.75-m telescope at SAAO .
We interpret these pulsations as non-radial g-modes with the same spherical degree \ell =1 , as suggested by the mean period spacing of 37.1 \pm 0.7 seconds .
We use a genetic-algorithm-based fitting method to find the globally optimal model parameters , including the stellar mass ( M _ { * } = 0.73 M _ { \odot } ) , the effective temperature ( T _ { eff } = 21 , 000 K ) , the mass of the atmospheric helium layer ( \log [ M _ { He } / M _ { * } ] = -6.66 ) , and the central oxygen mass fraction ( X _ { O } = 0.61 ) .
The latter value implies a rate for the ^ { 12 } { C } ( \alpha, \gamma ) ^ { 16 } { O } reaction near S _ { 300 } = 180 keV b , consistent with laboratory measurements .