For the stars that had both the veiling at J and the veiling at K measured one can determine the corresponding (J-K) colour. The procedure described by Meyer, Calvet & Hillenbrand (1998) was used here to compute the (J-K) colour.
Given that the
veiling at a wavelength 
is
the ratio of the excess flux to the stellar flux at that wavelength the
intrinsic
(J-K) excess would be
in the absence of extinction, and of thermal emission from foreground or
background dust at these wavelengths.
This may also be directly determined from the observed 
colour using
where 
is the intrinsic
colour of the stellar photosphere
based on the spectral type, 
is the visual extinction, and no
foreground or background dust emission is assumed.
For the numerical coefficient in equation 4.7 see Meyer,
Calvet & Hillenbrand (1998).
The 
intrinsic colour excess
calculated using equation
4.6 for the 16 stars for which both
rJ and rK
were computed using a K7V template star is shown in Column 1 of
Table 4.2. Column 2 contains the
predicted 
as
determined from equation
4.7 with 
the intrinsic colour
for a K7V star, taken as 
from Bessel & Brett (1998).
The predicted 
were
determined ignoring any reddening, i.e.
in equation 4.7
was taken to be equal to zero for all stars, and ignoring any dust
emission. This is clearly not the
case for most of the objects. However since, for a given star, the values
for the visual extinction and dust emission found in the literature
vary, it was chosen not to correct for these effects.
The predicted 
from the
veiling measurements in this work can be
compared with the values measured by Strom et al. (1989),
included in Table 4.2.
colour are quite big, as can be seen from Table 4.2. This
means that it is not easy to make a comparison with the observed 
colours.
Taking into account the large uncertainties in the predicted 
colour
deduced from the veiling measurements one finds no clear disagreement
between those predictions and the
observations. However, 
tends
to be systematically smaller,
that is to say bluer, than what the observations show. As mentioned
above, neither the extinction nor dust emission were taken into account
for the computation of
. Extinction or dust emission
causes 
to become redder
and thus closer to the observed values.
