## 4. Recommended fitting coefficientsThe resulting 20 sets of all 4 fit parameters were grouped in order to establish useful relations involving two parameters of a bursting star: , and , vs. observables. Perhaps the best method is defined by the following steps. 1. For each , values of corresponding to all listed were averaged to establish a unique relation , independent of gravity. 2. Parameters were averaged in all analysed spectra, which yielded the average value of (standard deviation). Unfortunately, normalization factors are much less useful for averaging purposes. They exhibited significant scatter due to numerical roundoff errors in the fitting procedure, and will not be used in the following sections. Table 2 gives four averaged values of , corresponding to each considered . The averaged spectral hardening ratio, . Such a value is fully consistent with earlier estimates, (cf. Lewin et al. 1993). Note, however, that 's discussed in this paper were determined form fits, which are not strictly blackbodies.
Now the whole fitting procedure has been repeated for each model
atmosphere, but with fixed and values of
given in Table 2. This has given the values
of chemical potential It is interesting to note, that the parameter © European Southern Observatory (ESO) 1997 Online publication: July 3, 1998 |