  We have carried out a detailed asteroseismic analysis of PG 1219+534. Our
analysis leads to the identification of the (k,l) indices of nine periods
observed in the star PG 1219+534, and to the determination of its structural
parameters. The periods all correspond to low-order acoustic modes with
adjacent values of k and with l=0, 1, 2, and 3. They define a band of unstable
modes, in close agreement with nonadiabatic pulsation theory. Furthermore, the
average dispersion between the nine observed periods and the periods of the
corresponding nine theoretical modes of the optimal model is only ~0.6%,
comparable to the results of a similar analysis carried out by Brassard et al.
(2001) on the rapid sdB pulsator PG 0014+067. On the basis of our combined
spectroscopic and asteroseismic analysis, the inferred global structural
parameters of PG 1219+534 are Teff = 33,600 +/- 370 K, log g = 5.8071 +/-
0.0057, log Menv/M* = -4.254 +/- 0.147, M* = 0.457 +/- 0.012 Msun, R/Rsun =
0.1397 +/- 0.0028, and L/Lsun = 22.01 +/- 1.85. Combined with detailed model
atmosphere calculations, we estimate, in addition, that this star has an
absolute visual magnitude MV = 4.62 +/- 0.06 and is located at a distance d =
531 +/- 23 pc (using V = 13.24 +/- 0.20). Finally, if we interpret the absence
of fine structure (frequency multiplets) as indicative of a slow rotation rate
of that star, we further find that PG 1219+534 rotates with a period longer
than 3.4 days, and has a maximum rotational broadening velocity of Vsin i <~
2.1 km/s.
