Astron. Astrophys. 356, 665-675 (2000)

2. Observations

Optical spectra of LB 3459 were obtained during several observation campaigns in the last years. In Table 1 we summarize these observations. The given resolution is measured from the He-Ar and Th-Ar comparison spectra.

We retrieved the three available high-resolution SWP spectra of LB 3459 from the IUE Final Archive (Table 2). Since LB 3459 is a binary, we used H I  Å , He II  Å , C IV  Å , N IV  Å , N V , and Si IV  Å in order to determine the average shifts from their rest wavelengths (Table 2). All these lines show the same deviations and are thus clearly of photospheric origin while e.g. Si III  Å (Fig. 5) appears at its rest wavelength in all spectra and hence, is dominated by interstellar absorption. The spectra are shifted then by these amounts and co-added (equally-weighted due to their similar S/N ratio). The influence of the orbital motion of LB 3459 is discussed in (Sect. 3.1).

Table 2. Observation log of the optical spectra of LB 3459 taken at ESO

© European Southern Observatory (ESO) 2000

Online publication: April 10, 2000
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