Vol. 565
In section 7. Stellar structure and evolution

The rapid evolution of the exciting star of the Stingray nebula

by N. Reindl, T. Rauch, M. Parthasarathy, K. Werner, J. W. Kruk, W.-R. Hamann, A. Sander, and H. Todt, A&A 565, A40

SAO244567 is the central star of the Stingray planetary nebula. The spectral type estimated from a spectrum taken in 1971 is B1 or B2, corresponding to a temperature of 21 000K. Subsequent spectra reveal a dramatic increase in the surface temperature. This investigation presents an analysis of spectra taken between 1988 and 2006. During this period, the temperature increased from 38 000K to a maximum of 60 000K in 2002. More recent observations indicate a drop in temperature after 2002. The evolutionary status of SAO244567 remains unclear, with a late thermal pulse or close binary evolution being the most likely explanations.