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Special Notice #201: Outburst of the symbiotic star V407 Cyg

March 12, 2010: Further to Maehara et al. (CBET 2199, D.W.E. Green, editor), the presumed symbiotic star V407 Cyg appears to be undergoing a very bright outburst, well outside of its previous range. This outburst was discovered independently by the team of K. Nishiyama (Fukuoka, Japan) and F. Kabashima (Saga, Japan), and by T. Kojima (Tsumagoi, Agatsuma-gun, Gunma-ken, Japan). Nishiyama and Kabashima observed the star at an unfiltered magnitude of 6.8 on 2010 March 10.813 (JD 2455266.313) and magnitude 6.9 on 2010 March 10.814 (2455266.814). Kojima observed the star at around magnitude 7 on two images taken using a Canon EOS 40D. This is well outside its previously stated range and may indicate a nova outburst in progress.
 
The AAVSO data archive for this object is sparse, and observations of this object are strongly encouraged. Spectroscopy of V407 Cyg is particularly encouraged given both the brightness of the source and the fact that its exact nature is unclear. Suggested classifications for this source include slow nova with either a Mira secondary or Mira component, or a symbiotic star. Spectroscopy and multicolor photometry may provide more information on the nature of this system, while visual observations and time-series photometry will be needed for tracking the overall light evolution of the system.
 
V407 Cyg is located at the following (J2000) coordinates:
RA: 21 02 09.85 , Dec: +45 46 33.0
 
Charts for V407 Cyg may be plotted using AAVSO VSP (http://www.aavso.org/vsp).
 
We note that the sequence has been updated to include more appropriate stars for its current magnitude range.
 
Please report all instrumental photometry and visual observations to the AAVSO via WebObs using the name "V407 Cyg".
 
This AAVSO Special Notice was prepared by Matthew Templeton.
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