Publication
International observational campaign of the 2014 eclipse of EE Cephei
Publisher:
EDP Sciences
Date:
07-2020
DOI:
10.1051/0004-6361/201937181
Abstract: Context. EE Cep is one of few eclipsing binary systems with a dark, dusty disc around an invisible object similar to ε Aur. The system is characterised by grey and asymmetric eclipses every 5.6 yr that have significant variations in their photometric depth, ranging from ∼0 . m 5 to ∼2 . m 0. Aims. The main aim of the observational c aign of the EE Cep eclipse in 2014 was to test the model of disc precession. We expected that this eclipse would be one of the deepest with a depth of ∼2 . m 0. Methods. We collected multicoloured observations from almost 30 instruments located in Europe and North America. These photometric data cover 243 nights during and around the eclipse. We also analyzed low- and high-resolution spectra from several instruments. Results. The eclipse was shallow with a depth of 0 . m 71 in the V band. The multicoloured photometry illustrates small colour changes during the eclipse with a total litude of order ∼+0 . m 15 in the B − I colour index. We updated the linear ephemeris for this system by including new times of minima, measured from the three most recent eclipses at epochs E = 9, 10, and 11. We acquired new spectroscopic observations, covering orbital phases around the eclipse, which were not observed in the past and increased the data s le, filling some gaps and giving better insight into the evolution of the H α and Na I spectral line profiles during the primary eclipse. Conclusions. The eclipse of EE Cep in 2014 was shallower than expected, measuring 0 . m 71 instead of ∼2 . m 0. This means that our model of disc precession needs revision.