4.3.2. Stellar Type O7
The four CCPs for the O7 case, viz. [P13-14] / [P9-12], [P9-12] /
[C4-8], [P12-13] / [C4-8] and [P13-14] / [C4-8] are displayed in
Figure 5. These
CCPs have been found to be sensitive enough to be used as
diagnostic tools.
Among these CCPs the most sensitive one is the CCP
[P12-13] / [C4-8] which distinguishes all the three
density distributions even if the colours are measured with a very
crude accuracy of 0.5 dex in [P12-13] and 0.2 dex in
[C4-8]. For the rest, it is required to achieve a colour
accuracy of < 0.1 dex to draw firm conclusions about density
distribution and 100.
Once again the r-2 law is the
most unambiguously placed in all these CCPs. The IRAS
measurements of the
Crawford &
Rowan-Robinson (1986)
sample, have been overplotted on the CCP [P13-14] / [P9-12]
(Figure 5a).
With the exception of one point close to the r-2 locus,
most of the points are scattered between the loci corresponding
to r0 and r-1 density distributions. A comparison
of this CCP for O7 (Figure 5a) with
that of O4 (Figure 4a)
suggests that O7 is a better description of the observations.
If the distances to the individual IRAS sources would be
available, then on luminosity grounds, this conclusion
could be strengthened further.