Short-term variations of LBV’s

Abstract

The short-term spectroscopic variations of LBV’s in relative quiescence are qualitatively similar to variations shown by normal supergiants of similar spectral type. In particular, in LBV’s of later spectral type and lower luminosity rotational modulation is more pronounced than in LBV’s of higher temperature and luminosity. The timescales in LBV’s are probably longer tahn in normal supergiants. This could be due to their higher luminosity.

The short-term variations of LBV’s during outburst are very complex and indicate that the details of LBV outbursts are still not understood. The behaviour of AG Car during rise to visual maximum is markedly different from the decline to minimum. This may indicate that a simple change of radius and temperature does not explain LBV outbursts.