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CI Cygni

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The symbiotic star, CI Cyg, has experienced only a few outbursts in its long recorded history. The outbursts of 1911 and 1937 were relatively modest in amplitude and duration. Then, between 1970 and 1978 CI Cyg experienced a major outburst phase, characterized by three maxima occurring on November 1971 (V=9.3), November 1973 (V=9.8) and August 1975 (V=8.7), with minima occurring in June 1973 and March 1975. One sharper minimum, centered on Oct 4, 1975 (at V=11.1), was caused by a total eclipse of the outbursting component by the M5.5 III companion.

CI Cyg entered a new major outburst phase in 2008, the first one after 30 years of relative quiescence. In August of 2010 it appeared it might be heading for a second maximum, similar to the behavior it exhibited in 1970's.

Prepared By: SXN
AAVSO 49 Bay State Rd. Cambridge, MA 02138 aavso@aavso.org 617-354-0484