Up: B[e] stars
We have listed in Table 3 all absorption features
appearing in our spectra. Half of them belong to well known
interstellar bands, whereas the remainder is composed by lines
belonging to a hot star. Among the interstellar lines we find those
corresponding to NaI (M.1) and K I (M.1) which cannot be resolved
into components due to lack of resolving power. We can thus not
decide if they come from the interstellar or from the circumstellar
medium. If the observed equivalent widths of the interstellar lines
are taken at face value, we can use Herbig's (1975) relation between
strength and B-V color excess to derive an estimate of the latter.
From four features, we derive 0.41 0.48 which speaks in favor of a
rather low value of E(B-V). It should be added that the large
uncertainty attached to our result is quite natural when dealing
with equivalent width-color excess relations. Brosch et al. (1978)
had found a value of 0.5, whereas Bergner et al. (1990) found 2.1.
However all values have a rather large uncertainty attached.
Among the lines attributable to the hot component, we find
lines belonging to CIII and O II. Such lines are observable in
stars of spectral types between O 7-B 0.5 (C III) and O9-B3 (O II).
As a compromise we adopt a spectral type of about B 0. Nothing can
be said on the luminosity of the star, since both elements show a
positive luminosity effect. The spectral type found agrees well
with the 28 000 K star found by Bergner et al. (1990).
Absorption lines present in MWC 342
The first column provides the observed wavelength, the second
the equivalent width, the third the theoretical wavelength and
the last the identification. IB = interstellar band; Herbig =
Herbig (1975); Sanner et al. = Sanner et al. (1978).
Up: B[e] stars
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