We present an analysis of the Far Ultraviolet Spectroscopic Explorer (FUSE ) spectra of five V1093 Her (PG 1716+426) stars, the subgroup of hydrogen-rich subdwarf B stars that exhibit very low amplitude, long-period luminosity variations. Our primary aim is to investigate whether these stars display abundances which differ from those observed in the nonvariable sdB stars and also in the shorter period V361 Hya variables. For the light elements and for those beyond the iron peak, our abundances are consistent with the trends observed in earlier studies. For the important iron peak elements Ti, V, Cr, Mn, Fe, Co, and Ni, which are thought to be directly linked to the driving mechanism in both long-period and short-period variables, the abundances determined in the V1093 Her stars appear very homogeneous and exhibit mild enrichments (by factors of 2Y5 for Cr, Mn, Fe, and Co) over the solar value. However, these abundances do not differ appreciably from those measured in a sample consisting of constant stars and one short-period pulsator. The implications of these findings for current models which involve both diffusion processes and stellar winds to account for the driving of nonradial pulsations in sdB stars are discussed.

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???The original publication is available at www.springerlink.com???. Copyright Springer. [Full text of this article is not available in the UHRA]We present a FUSE abundance analysis of EC14026 stars. We compare the abundances of heavy elements in the atmospheres of EC14026 stars to non-pulsating stars with similar atmospheric parameters, and investigate whether weak stellar winds could explain the coexistence of variable and non-variable sdB stars in the log g ??? Teff diagram. We also present preliminary results on time-dependent diffusion calculations of iron in presence of radiative levitation and mass loss, and show how weak stellar winds can affect the diffusive equilibrium between gravitational settling and radiative support

We present the results of an observational campaign for the long-period variable subdwarf B star PG 1338+ 481. Seven continuous weeks of observing time at the Steward Observatory 1.55 m Kuiper telescope on Mount Bigelow, Arizona, and the 1.3 m MDM telescope at Kitt Peak rendered $250 hr of simultaneous U/R time series photometry, as well as an extra $70 hr of R-band-only data. The analysis of the combined light curves resulted in the extraction of 13 convincing periodicities in the 2100-7200 s range, with amplitudes up to $0.3% and $0.2% in the U and R, respectively. Comparing the ratios of amplitudes in the two wave bands to those predicted from theory suggests the presence of dipole modes, a notion that is further supported by the period spacing between the highest amplitude peaks. If confirmed, this poses a challenge to current nonadiabatic theory. At the quantitative level, we find that the distribution of the observed period spectrum is highly nonuniform and much sparser than that predicted from a representative model. We provide a possible interpretation in the text. The asteroseismological analysis attempted for PG 1338+481 on the basis of six observed periodicities believed to constitute consecutive dipole modes renders encouraging results. Fixing the effective temperature and surface gravity to the spectroscopic estimates, we successfully isolate just one family of optimal models that can reproduce the measured periods to better than 1% . While the stellar parameters thus inferred must be regarded as preliminary, the achieved fit bodes well for future asteroseismic analyses of long-period variable subdwarf B stars.

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