Spectral Variability of the Unusually Peculiar Be Star XX~Ophiuchi

Extensive high-resolution spectroscopic monitoring of the peculiar ``iron'' star XX Oph have been carried out since 2002 in the three spectral regions, containing the He I 5876+DNa I, Hα, and He I 6678 Å lines. The star showed a deep, ∼2 mag and 400-day long brightness minimum at that time. The spectrum had a strong variability during the minimum with a noticeable increasing (excluding the DNa I lines) of the emission component and disappearance of the blue-shifted P Cyg-type absorption component in the He I lines. An eclipse of the hot component by the cool giant companion is the easiest way to explain the brightness minimum of XX Oph. It is found that the photometric and spectroscopic variability of XX Oph during the eclipse had many similarities with the variability of the symbiotic star BF Cyg, and probably XX Oph is another example of an intermediate-mass symbiotic star with a cool M5--7 II and a hot subdwarf stars.