AAVSO Special Notice #140
Outburst of the cataclysmic variable IQ Eri
December 29, 2008
As reported in CBET 1633 (D.W.E. Green, editor), the cataclysmic variable IQ Eridani (== 1RXS J025538.2-224655) was detected in outburst by L.A.G. Monard (Pretoria, South Africa) on 2008 December 20.880 UT (JD 2454821.380) at an unfiltered magnitude of CR = 14.1, and was found to have brightened to CR = 13.2 by 2008 December 25.789 UT (JD 2454826.289). Monard also indicated large amplitude, irregular variations of around 0.65 magnitude, and both the outburst and irreguar variations were confirmed by M. Bonnardeau (Chateau Bernard, France) in a post to cvnet-discussion; Bonnardeau found the star had brightened to an unfiltered magnitude of around 12.7 with irregular variations around 1 magnitude. P. Wils (Hever, Belgium) noted (via T. Kato, vsnet-alert 10844) that ASAS-3 photometry (Pojmanski 2002, AcA 52, 397) indicates that the system first showed signs of activity on or about 2008 December 11.12 (JD 2454811.62; m(V) = 12.63), reaching a maximum on 2008 December 14.12 (JD 2454814.62; m(V) = 11.85). This is the first known outburst of this system. The subtype is not known; the strong, irregular variations and the fact that it is a strong X-ray source suggest it may be a magnetic system such as an intermediate polar. Time series observations of this object are requested to better understand the system, and to determine the orbital period, the spin period of the white dwarf, or both if they are detectable. IQ Eri is located at the following (J2000) coordinates (from A. Henden): RA: 02 55 37.94 , Dec: -22 47 02.3 Finder charts for IQ Eri may be plotted for IQ Eri using VSP: http://www.aavso.org/observing/charts/vsp/index.html?pickname=iq%20eri Comparison stars are not yet available for this star, so please indicate what comparisons you use when submitting data. Please submit all observations to the AAVSO as "IQ Eri". This AAVSO Special Notice was prepared by M. Templeton. --------------------------------------------------- SUBMIT OBSERVATIONS TO THE AAVSO Information on submitting observations to the AAVSO may be found at: http://www.aavso.org/observing/submit/ SPECIAL NOTICE ARCHIVE AND SUBSCRIPTION INFORMATION A Special Notice archive is available at the following URL: http://www.aavso.org/publications/specialnotice/ Subscribing and Unsubscribing may be done at the following URL: http://www.aavso.org/publications/email/