WROCŁAWSKA STRONA HELAS-a

All computations were performed using Warsaw-New Jersey evolutionary code of Paczyński and linear nonadiabatic pulsation code of Dziembowski. For description of the codes see Pamyatnykh (1999).

We consider various masses and chemical composition (X, Z). Moreover, two chemical mixtures were taken into account: the old one (GN93=Grevesse & Noels 1993) and the new one (A04=Asplund et al. 2004). We make accessible results obtained with the OPAL and OP opacity tables. For temperatures log T ‹ 3.95 we use always the Aleksander & Ferguson (1994) opacities. The presented results were obtained for zero rotation velocity. In the near future we are going to extend the model grid in this parameter.

Recent results for nonlinear radial pulsation of β Cephei stars are also included.

Some computations for solar like oscillations are also available.


BIBLIOGRAFIA:
  • Asplund M., Grevesse N., Sauval A.J., 2004, ASP Conf. Ser, 336, 25
  • Grevesse N., Noels A., 1993, in Pratzo M., Vangioni-Flam E., Casse M., eds., Origin and Evolution of the Elements, Cambridge Univ. Press, p. 15
  • Pamyatnykh A.A., 1999, Acta Astr., 49, 119


Stellar oscillations were calculated from ZAMS to TAMS. The oscillation files are called nad***.mrt, and are packed for each mass. The structure of these files is as follows:


first line:

M=... Teff=... logL=... R=... logg=... Vrot=...

where

Mthe stellar mass in solar units
TefflogTeff
logLlogL/L
Rthe stellar radius in solar units
logglogg

second line:

l n sig P[hrs] fa[c/d] fn[c/d] COMPLEX F ekg/ek eta

where

lthe spherical harmonic degree, l
nthe radial order, n
sig
the dimensionless frequency defined as sig=omega/sqrt(4*Pi*G*avr_ro)
P[hrs]oscillation period in [h]
fa[c/d]adiabatic oscillation frequency in [c/d]
fn[c/d]adiabatic oscillation frequency in [c/d]
COMPLEX F(two values) the ratio of the radiative flux perturbation to the radial displacement at the level of the photosphere
ekg/ekratio of the gravitational energy to the total kinetic energy; 0 for "pure" pressure modes, 1 for "pure" gravity modes
eta
instability parameter defined as η = sig=omega/sqrt(4*Pi*G*avr_ro)
where W is the work integral. For unstable modes we have η > 0. The values of the η parameter change from -1 (damping everywhere) to +1 (driving everywhere)
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