AAVSO: American Association of Variable Star Observers

Observing the Low States of VY Scl Stars (Abstract)

Volume 45 number 1 (2017)

Linda Schmidtobreick
Eurpean Southern Observatory, ESO Vitacura, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago de Chile, Chile; lschmidt@eso.org


(Abstract only) Novalikes just above the period gap play an important role in our understanding of the evolution of cataclysmic variables. Most of them belong to the group of SW Sextantis stars and experience very high mass transfer rates. This results in extremely hot, bright and dense accretion discs which do not allow to observe the stellar components in these binaries. To therefore get information about the physical parameters of these objects, i.e. the masses of the two components, the stars need to be observed in a low state when the accretion is at least partly suppressed. Many of the novalike stars are known to experience such low states that are also called VY Scl low states. Within a large campaign, we have monitored these stars photometrically and triggered time resolved spectroscopic ToO observations when they went into a low state. I present some results of this campaign and would like to discuss the possibility of restarting it with the help of the AAVSO.