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Alert Notice 572: AG Dra monitoring requested

April 3, 2017: Dr. Rudolf Gális (Pavel Jozef Šafárik University (Slovakia)) and colleagues have requested AAVSO assistance in observing the symbiotic variable AG Dra. Observations are requested as a follow-up to spectroscopic observations and in order to monitor the system for an anticipated outburst.

Dr. Gális writes: "AG Dra is one of the best studied symbiotic systems, which undergoes characteristic symbiotic activity with alternating quiescent and active stages. The latter ones consist of several outbursts in intervals of about 1 yr. After seven years of flat quiescence following the 2006-08 major outbursts, in the spring of 2015, AG Dra...[entered the active stage]...with...two minor outbursts (in 2015 and 2016) up to now. Such behaviour is quite unusual in the photometric history of AG Dra, so the further systematic photometric monitoring of this symbiotic binary is highly desirable. We expect the next outburst of AG Dra in the late spring of 2017..."

Daily monitoring of AG Dra (V~7.9-10.3) in UBV(RI) filters is requested beginning at once and continuing until further notice. Visual observations are welcome and are encouraged. When the outburst occurs, revised observing instructions will likely be issued via an AAVSO Special Notice. Observers are urged to subscribe both to Alert Notices and Special Notices so as to be kept informed.

Coordinates for AG Dra:  R.A. 16 01 41.01  Dec. +66 48 10.2    (2000.0)

Charts: Charts with a comparison star sequence for AG Dra may be created using the AAVSO Variable Star Plotter (VSP).

Please submit observations to the AAVSO International Database using the name AG DRA.

For more information on symbiotic variables (Z And stars), please visit the Z And section of the AAVSO's Variable Star of the Season webpages. This campaign is being monitored on the AAVSO Observing Campaigns webpage and is being followed on the Campaigns and Observation Reports Forum at https://www.aavso.org/ag-dra-observing-campaign.

This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.

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