We have calculated the magnitudes for
the hot and cold components, assuming total secondary eclipse, that is, at
the
secondary minimum the only light contribution is from the bigger, hotter
star. This last hypothesis is consistent with both components being main
sequence stars, as we show below. The alternative hypothesis of
a cooler, evolved star occulting its companion in the primary
eclipse is less compatible with the value of the 
index
at phase 0.0. Interstellar reddening for each component
has been computed following the method described by
Crawford (1978), and
using
the standard relations for the intrinsic indices given by
Perry et al.
(1987).
We found E(b-y)=0.617 and E(b-y)=0.638 for the primary and secondary
stars respectively. We adopted the mean of the two
determinations,
weighted with the rms dispersion of the c1 index, which gives a value
of E(b-y)=0.621 as the reddening
for the system. Table 2 (click here) list the intrinsic magnitudes and
indices
for both components. Errors given for the primary star are the rms dispersion
of the six points averaged at the bottom of the secondary eclipse. For the
cold component the errors listed are the propagation errors through the
formulae used in the decoupling. The intrinsic indices are compatible with
spectral types B0.5V and B1V, assuming the mean values as a function of
spectral type given by Crawford (1978).
| name | y0 | (b-y)0 | m0 | c0 | |
| CR Cas Hot | 9.040 | -0.126 | 0.078 | -0.034 | 2.602 |
| 2 | 6 | 11 | 24 | 1 | |
| CR Cas Cold | 9.827 | -0.104 | 0.136 | 0.048 | 2.614 |
| 13 | 22 | 52 | 84 | 9 |
| MV | FV |  |  (K) |  | log |
 | d(pc) | MK | |
| CR Cas Hot | -3.8 | 4.19 | 6.7 | 26010 | -6.4 | 4.26 | 12.6 | 3680 | B0.5 V |
| 4 | 3 | 1.6 | 400 | 5 | 20 | 1.0 | 750 | ||
| CR Cas Cold | -3.0 | 4.14 | 5.8 | 22780 | -5.3 | 3.91 | 9.8 | 3680 | B1 V |
| 4 | 3 | 1.4 | 530 | 5 | 21 | 1.0 | 750 |
We used the empirical calibration of
Balona & Shobbrook (1984) to calculate
the absolute magnitudes and distances of both components separately. The
obtained distances, 
and 
parsec, show a good internal agreement and are coherent
with the reddening estimated. We will assume the weighted mean,
as the distance of the system. Final absolute magnitudes have been
calculated using the observed apparent magnitudes and the assumed mean
distance.
To estimate the radii we have first computed the visual surface brightness parameter FV (Barnes & Evans 1976), by means of the calibration in terms of (b-y) given by Moon (1984). The effective temperature has been derived comparing the obtained photometric indices with the synthetic indices computed by Lester et al. (1986), using the interpolating formula given by Balona (1994). From the obtained temperatures we have derived the bolometric corrections using the Balona (1994) relationship. Masses have been estimated from the evolutionary models of Claret & Giménez (1992), using the interpolating formula computed by Balona (1994). The computed values are listed in Table 3 (click here).
Although there are not radial velocity curves published for this binary
system, we have done a preliminary estimation of the
radii of both components relative to the orbit (
, 
) and the
inclination of the orbit (i), by using the EBOP code, written by
Etzel (1975).
Initial values to run EBOP
were assumed from Table 3 (click here). Because the light curves show
appreciable
variation at the bottom of the primary eclipse, specially in the u filter
(see Figs. 1 (click here), 2 (click here), 3 (click here) and 4 (click here)),
we
computed the EBOP solution with the data obtained in the last campaign
(292 points). We found that the best theoretical light curves correspond to
stars with 
and 
for the hot and cold component
respectively, and 
.