8.4 Comparison of Methods

It is evident from Table 6.3 and Table 6.3 that both procedures, that of Fabregat and Torrejon (1998) (hence forth FT) and that of this chapter (hence forth HSP), are valid at the 3 level. It can also be seen however that the results produced by FT are overwhelmed by their associated errors, with HSP producing errors smaller than their associated results but still too large to enable further work. FT also allows derivation of the intrinsic star flux, whilst HSP relies on the literature for this.

Both procedures therefore have their merits, with slightly more secure results about the disc coming from HSP, whilst a more overall picture is produced by FT. However it necessary to ask whether Strömgren photometry is a valid approach for observing Be star discs, as it may not be possible to achieve more accurate results due to the excesses being overwhelmed by the continuum. This effect can be plainly seen in Figure 6.2.

8.4.1 Chapter 8 Summary

The problem faced in this chapter has been that the Strömgren method requires very precise measurements to derive stellar parameters. In the case of Be stars these measurements are upset by the circumstellar component, but the circumstellar component is too small to accurately compute, but is large enough to inhibit further calculations.

This chapter must conclude by stating that unless more accurate methods of separating the circumstellar excess from the continuum can be derived Strömgren photometry of Be stars is not viable. Any method used must be less iterative than that of FT to reduce the compounding of errors, but preferably rely more on the observations in hand, unlike the HSP procedure. Without such methods the advantages of the Strömgren filters outlined in Chapter 6 will remain beyond the grasp of Be stars.