  The spectral energy distribution (SED) of the TT Ari system, which is well
known from published IUE and optical photometric observations, was modeled by a
steady-state accretion \alpha-disc around a white dwarf. Parameters of the
system were derived from time-resolved optical spectral observations in the
bright state that we obtained in Sep. 1998. The radial velocity semi-amplitude
of the white dwarf (33.8 +/- 2.5 km/s) and corresponding mass function (f(M) =
5.5 +/- 1.2 *10^{-4}~ M_sun) were derived from the motion of the emission
components of Balmer lines. The mass ratio q (\approx 0.315) was evaluated from
the fractional period excess of the superhump period over the orbital period
\epsilon (\approx 0.085), and a secondary mass range (0.18 - 0.38 M_sun) was
estimated from the orbital period. Therefore, the white dwarf mass range is
0.57 - 1.2 M_sun and the inclination angle of the system to the line of sight
is 17 - 22.5 degrees. The adopted distance to the system is 335 +/- 50 pc. To
fit the observed SED it is necessary to add a thermal spectrum with T \approx
11600 K and luminosity \approx 0.4 L_disk to the accretion disc spectrum. This
combined spectrum successfully describes the observed Balmer lines absorption
components. Formally the best fit of the HeI 4471 line gives minimum masses of
the components (M_RD = 0.18 M_sun and M_WD = 0.57 M_sun), with the
corresponding inclination angle i = 22.1 deg and mass-accretion rate \dot M =
2.6 * 10^{17} g/s.

Solar and Stellar Astrophysics