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"Peremennye Zvezdy", Prilozhenie, vol. 6, N 28 (2006)

CH Cyg: Unusual IR Fading of the System in 2006

O. Taranova, V. Shenavrin
Russia, Moscow, Sternberg Astronomical Institute

ISSN 2221–0474

Received:   14.11.2006;   accepted:   16.11.2006
(E-mail for contact: taranova@sai.msu.ru)

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Star Name: CH Cyg, BD+49 2999, HD 182917, HIP 095413, IRC +50294, SAO 031632 Coordinates (J2000): 19 24 33.07, +50 14 29.1 Variability type: ZAND+SR;   Limits, System: 0.65-2.4 (J);     Period: Epoch: JD

Remarks:

We inform on an extreme fading of the unique symbiotic star CH Cyg in the near infrared (1.25 - 5 microns). During our observations of the system between 1978 and the end of 2006, such an IR fading is observed for the first time. For example, compared to the system's IR fading in 1996 (Taranova and Shenavrin, 2004), its brightness in the J filter (1.25 microns) has additionally decreased by approximately 0.7 mag. The Figure displays variations of the system's J-band brightness in 1978-2006. The absolute lowest J-band brightness ever observed is marked with the arrow at JD 2454049. The horizontal line notes the minimum of 1996.

References:

Taranova, O.G., Shenavrin, V.I. , 2004, Astron. Reports, 48, 813