Symbiotic star ci Cygni is going on eclipse these last weeks with a Mv dropping to 11.4. The period of the system is about 853 days and maximum is awaited for mid November

At the same time the system has an ongoing outburst from the disk around the white dwarf whose began in July and certainly continue and repeated for months.

The conjunction of an outburst and an eclipse is a unique chance for probing the inner regions of this strange object composed by a M dwarf type star and a White dwarf.

The Aras group began a spectroscopic campaign, leaded by François Tessier, complementary from the AAVSO photometric campaign.

If the beginning of the eclipse was without major surprise, we saw these last days unexpected striking changes. For my first spectra is this campaign i discover a bright Ha intensity surge, confirmed by laters obsevation from C.Buil and Ew calculation from F.Teyssier. The Ha region enter on an unexpected activity with every day change in Ha intesity and Ew. The ratio Ha/Hb change quickly too and the photometry follow the movement.

What could make Ha spectrum varying quickly ? In other eclisping symbiotic stars, AX Per for ex  we knows somes geometric effects in relation with the orbital phase. But so major variaitions was unexpected.

One thing is that we explore inner region of the WD disk, perharps inhomogeneous, as ingress phase is near the november totality. Or it is a new activity of the system.

So the quest continue ! The cosmos is always moving.


All spectra are flat fielded corrected (2700°k), Instrumental response corrected (Altair), not normalized, continuum rescale at 1. 2H to 2H30 exposure with a LhiresIII 2400gr/mm and an Atik314L+ Reduction with AudeLa/Spc_Audace