We present key sample results of a systematic survey of the pulsation properties of models of hot B subdwarfs .
We use equilibrium structures taken from detailed evolutionary sequences of solar metallicity ( Z = 0.02 ) supplemented by grids of static envelope models of various metallicities ( Z = 0.02 , 0.04 , 0.06 , 0.08 , and 0.10 ) .
We consider all pulsation modes with l = 0 , 1 , 2 , and 3 in the 80–1500 s period window , the interval currently most suitable for fast photometric detection techniques .
We establish that significant driving is often present in hot B subdwarfs and is due to an opacity bump associated with heavy element ionization .
We find that models with Z \geq 0.04 show low radial order unstable modes ; both radial and nonradial ( p , f , and g ) pulsations are excited .
The unstable models have T _ { eff } \buildrel < \over { \sim } 30,000 K , and log g \buildrel < \over { \sim } 5.7 , depending somewhat on the metallicity .
We emphasize that metal enrichment needs only occur locally in the driving region .
On this basis , combined with the accepted view that local enrichments and depletions of metals are common place in the envelopes of hot B subdwarfs , we predict that some of these stars should show luminosity variations resulting from pulsational instabilities .