An attempt to describe the nature of the stars will now be made. An
exhaustive period analysis of the available data has been made and the most
likely frequencies have been established by different methods. Also, 
photometry has been secured and, from it, physical parameters such as
and log g for the stars can be extracted.
| physical param | KW 045 | KW 154 | KW 204 | KW 207 | KW 323 | KW 445 |
| Mv | 1.96 | 2.19 | 0.50 | 1.24 | 1.62 | 1.76 |
 | 1.84 | 2.09 | 0.38 | 1.10 | 1.74 | 1.90 |
|
| 3.89 | 3.88 | 3.89 | 3.90 | 3.89 | 3.90 |
 | 3.80 | 4.00 | 2.90 | 3.75 | 3.75 | 3.75 |
| Q | 0.013 | 0.025 | 0.009 | 0.014 | 0.012 | 0.016 |
| pulsat mode | 3H | 1H | 3H/? | 3H | 3H/? | 3H |
Cluster membership was established with the advantages of the Strömgren
photometry of the cluster by Crawford & Barnes (1969)
and the
UBV photometry by Johnson (1952), a calibration by
Nissen (1988) which follows
previous calibrations by Crawford (1975, 1979)
for the A and F stars and by Shobbrook (1984) for early type stars which have been already employed in
previous analysis of open clusters (Peña & Peniche 1994).
From the distance
to the stars evaluated, a mean distance and standard deviation was calculated;
the criteria for membership was established as the distance within one sigma of
the mean. (
pc); this criteria is fullfilled by 48 stars. Once this
was done, average parameters such as reddening (
mag),
and chemical composition, ([Fe/H] = 0.068 
0.1191) were determined. The
assigned membership for five of the observed stars is in agreement with the
above mentioned criteria and with the membership probability
assigned by Jones & Cutworth (1983) from proper motion studies.
Once the reddening has been determined it was
possible to calculate the
unreddened colors (b-y)0, m0 and c0. Then, the location
of each star
was fixed at the (b-y)0 vs. c0 diagram of
Relyea & Kurucz (1978);
from it, the surface temperatures and gravities, log 
and log g,
were determined
for each star. Another way in which this latter quantity can be determined is
through the calibrations of Petersen & Jorgensen (1972)
or by the calibrations
of Pérez et al. (1989). A comparison of the values determined from the three
calibrations yields the following results: A fair agreement is found between the
values determined by Petersen & Jorgensen (1972) prescription with that of
the Relyea & Kurucz (1978) diagrams. The linear regression for these sets is
of 0.94. The mean of the differences is 3 K with a standard deviation of 52 K A
larger systematic difference is found from the aforementioned temperatures from
those derived from Pérez et al. (1989). The mean of the differences is 1788 K
with a standard deviation of 458 K. However, since the temperatures of Perez do
not correspond to those deduced for their spectral types the final consideration
for the temperatures were those of the diagrams
of Relyea & Kurucz (1978) deduced from the original Strömgren photometry. The values considered for each
star are listed in Table 13 (click here). The bolometric correction for each star was taken
from the compilation of Lang (1991) through the log
values already mentioned.
With this, for each star was calculated.
The pulsation mode is determined from the well-known relation (Petersen & Jorgensen 1972; Breger 1990) in which the main period for each star determined in the past sections was taken.
The results derived in the present paper are still in agreement with the
basic conclusion of Breger (1980) that "it is interesting to speculate that the
preference for the second and third overtone may be connected with the position
of the star in the hot part of the instability strip, where theoretical models
have predicted pulsation in overtones (Stellingwerf 1979)". The numerical
values obtained are also in agreement with those previously determined. For
example, negligible reddening has been found (Crawford & Barnes 1969),
and a
distance modulus of 6.166 was determined (Nicolet 1981;
Anthony-Twarog 1982)
The age of the cluster has been fixed after establishing physical
characteristics such as log and log g for each star in the theoretical grids
of Relyea & Kurucz (1978). The location of the hottest stars in the
evolutionary tracks of VandenBerg (1985) agrees with his own conclusion that the
isochrone that best describes the position of the
stars is that of 
yr for a metallicity of Z = 0.169. It should be remarked, however, that KW
204 and more pronounced KW 154 do not lie in this track.
From models of Iben (1967), Tsvetkov (1989)
determined ages for each of the variables but
the spread of the ages is large, of 12.64 108 yr, with KW 204 much younger than
the rest. On the other hand, from the models of Paczynski (1970),
also reported
by Tsvetkov (1989), the ages of all the stars are practically the same, around
yr. The same result is also found for all the stars if more
recent models, those of Meynet et al. (1993), which consider
overshooting, are utilized but with a higher value of 
yr. The
compilation of Lang (1991) lists 
yr for Praesepe.