Special Notice #152: Increased activity in the symbiotic star AX Persei

AAVSO Special Notice #152

Increased activity in the symbiotic star AX Persei
April 6, 2009

U. Munari et al (CBET 1757, D.W.E. Green, editor) notes that the symbiotic star AX Per has brightened significantly and become bluer in color between 2009 February 28 and 2009 April 1.  The star has increased from B=12.56 to B=11.55, and changed from (B-V) = +1.08 to +0.82.  This is the brightest AX Per has been since the outburst of 1988-1992. Spectrophotometry of the star shows the presence of bright, high-ionization lines.  Overall, the spectrum indicates the central engine of the symbiotic star has "switched on", increasing in both luminosity and temperature.  This activity may be a precursor to a major outburst; Munari et al indicate AX Per exhibited similar behavior about one year prior to the 1988-1992 outburst.

Increased monitoring of AX Per is encouraged, both visually and with filtered photometry.  Observers with multiple filters are encouraged to transform their data to a standard system, to enable to calibration of all magnitudes and colors.  Intensive time-series observations are not critical at this time, but may be requested in the future.  Please obtain the highest signal-to-noise data feasible (S/N 50 or higher).

AX Persei is located at the following (J2000) coordinates:

RA: 01 36 22.70 , Dec +54 15 2.0

Charts for AX Persei may be plotted using AAVSO VSP: http://www.aavso.org/observing/charts/vsp/index.html?pickname=AX%20Per

Please submit all data to the AAVSO using the name "AX PER" (AUID 000-BBD-098).

This AAVSO Special Notice was prepared by M. Templeton.


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