Astron. Astrophys. 355, 607-616 (2000)

4. Conclusions

Our photometry of WR 137 reveals only small amplitude ( 0.03 mag in the V passband) random light variations. No periodicity could be found. These variations should be attributed to the continuum and they are probably due to dynamical wind instabilities.

WR 140 exhibited remarkable light variations and a shallow light dip is seen in all passbands shortly after periastron passage in 1993. The light attenuation lasted until 1997 or even 1998, probably because of a dust envelope built around the WR star by wind-wind interaction at periastron passage. The dust envelope was gradually dispersed. From the wavelength dependence of the light attenuation, we find strong evidence for Rayleigh (Mie-like) scattering, contributing to the opacity, in addition to electron scattering.

For WR 148, our photometric study confirms the 4.317364 d light variation, but reveals occasional scatter, disturbing the light curve shape. On one occasion, we see a flare-like event at a phase when the companion is in front. Our photometry reveals long-term variations of the mean light and, possibly, of the amplitude of the regular variation. There is some evidence for a periodicity of the long-term light variation and a 4 year cycle cannot be ruled out.

Our photometry of WR 153 is consistent with the quadruple model for this star and both the 6.6884 d and the 3.4696 d periods are seen in the light. In pair A (6.6884 d period) we found evidence for an atmospheric eclipse, in agreement with the results of other works, while in pair B (3.4696 d period) the eclipse is probably photospheric (core eclipse).

© European Southern Observatory (ESO) 2000

Online publication: March 9, 2000
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