Astron. Astrophys. 344, 607-613 (1999)

2. Observations

Table 1 gives the IUE observations. There are two periods of IUE observations that have not been published in previous publications: May/June 1994 and from February to July 1996.

Fig. 1. Phase dependence of the continuum fluxes. Fluxes at 1320 Å (solid lines), 1520 Å (dotted lines) and at 3000 Å (dashed lines) were normalized to phase =0.484 and are given as function of phase .

Fig. 2. Phase dependence of some emission line fluxes. Fluxes for the lines N V 1240 (solid lines), O III ]1663 (dotted lines) and O IV ]1401 (dashed lines) were normalized to phase =0.484 and are given as function of phase .

Table 1. Low resolution IUE observations of SY Mus, with exception of the spectra SWP 56975, which was observed at high resolution. Exposure times, , are given in minutes. The Julian Date is given as 2 440 000+JD, the phase corresponds to the ephemeris of Eq. (1).

Table 1. (continued)

2.1. Continuum fluxes

In Table 2 we give the observed continuum fluxes at three wavelengths where no significant emission lines are present. In the last line of Table 2, we add the fluxes at phase =0.484 taken from PVN95 as a function of the binary phase and normalized to phase 0.484. Some data points were taken from PVN95. The variation at 1320 Å and 1520 Å shows a deep minimum (flux close to zero) between the phases 0.9 and 0.1. The variation at 3000 Å differs in two aspects from the other two: the minimum flux at mid eclipse is higher and its intensity variation is less steep; the flux variations at 1320 Å and at 1520 Å indicate that the hot star is totally eclipsed whereas the flux variations at 3000 Å tell us that the nebular continuum is only partially eclipsed.

Table 2. Observed continuum fluxes at three different wavelengths in units of 10^-14 erg cm^{- 2} sec^-1 ang^-1. The phase corresponds to the ephemeris given in Eq. (1). The last line presents the continuum fluxes measured at phase 0.484 as given in PVN95.

2.2. Emission lines

Tables 3 and 4 give the observed flux and Fig. 2 shows the behavior of the lines N V 1240, O III ] 1663 and O IV ], Si IV ] at 1401. In Fig. 2 they are plotted, together with the data of Table 2 of PVN95, as function of the binary phase and normalized to phase 0.484. Some data points were also taken from PVN95. The lines of C IV 1549 and He II 1640 are saturated in all spectra. In both IUE short (1200 Å-2000 Å) and long (2000 Å-3200 Å) wave spectra, lines of O III , N III , N IV , C III , Si III , and the blend of O IV /Si IV are also clearly present and their fluxes can be reliably measured. The same applies to He II , Mg II , Mg V , and O III in the long wavelength spectra.

Table 3. Emission line fluxes observed with the SWP camera of IUE. Flux intensities are given in units of 10^{- 13} erg cm^-2 sec^-1. The phase corresponds to the ephemeris given by Eq. (1). The last line contains the line fluxes measured at phase 0.484 as given in PVN95.
Notes:
: The O IV ] multiplet is blended with Si IV resonance doublet at approximately equal strength.
sat: Saturated line.

Table 4. Emission line fluxes observed with the LWP camera of the IUE. Flux intensities are given in units of 10^{- 13} erg cm^-2 sec^-1. The phase corresponds to the ephemeris given in Eq. (1). The last line presents the line fluxes measured at phase 0.484 as given in PVN95.

As well as the continuum fluxes, the emission lines fluxes are clearly phase dependent. Fig. 2 depicts the bevavior for the lines N V 1240, O III ]1663 and O IV ]1401. Contrary to the continuum fluxes at 1320 Å and at 1520 Å, the emission lines are partially eclipsed.

© European Southern Observatory (ESO) 1999

Online publication: March 18, 1999
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