As mentioned in Section 6.1.1, the required parameters to compute line profiles with the method described above are: the effective temperature and radius of the central star, the density at the base of the flow and the radial dependencies of the temperature, velocity and turbulent velocity of the flow.
The properties of the central star were chosen to be those typical of a
T Tauri
star in the Taurus-Auriga complex: 
, 
and Teff = 4000 K [Hartmann et al. 1990]. These were kept constant in all models
considered.
The flow properties were treated as free parameters. These are the
density at the base of the flow, i.e.
at 
, and the flow
temperature 
, velocity 
and turbulent velocity
. The density translates into a wind mass loss rate or into
an accretion rate, depending on the model, via the conservation
equation 
.
The aim of the study performed here is to try to determine which flow characteristics produce Pa Beta and Br Gamma line profiles similar to those observed. The temperature structure of flows in T Tauri stars is one of the big unknowns about these objects [Hartmann et al. 1990,Muzerolle et al. 1998]. In general, the flows considered here are treated as isothermal at a temperature of 7000 K, although departures from this are also tried.
For wind models, the velocity dependence with radius is, in general, that used by Natta, Giovanardi & Palla (1988) parametrized as
where, 
is the velocity at 
, 
is the terminal
velocity, and 
is the stellar radius. Again, departures from this
are also tried. For accretion models, the
velocity corresponds to the free fall velocity from a radius
, i.e.
In these models accretion is treated as spherically symmetric therefore they are not necessarily a good representation of situations such as magnetospheric accretion.
The turbulent velocity is taken to be relatively low (~ 40 km/s) at all radii to start with and it is increased, if necessary, at smaller radii so that the resulting line profiles are as broad as those observed.
