Seeing the Evolution of Cataclysmic Variables for the First Time

Cataclysmic Variables are expected to have long term cycles, where the accretion rate changes greatly on time scales of centuries to millennia. For the first time, I and my colleagues can test the prediction by constructing century-long light curves for many cataclysmic variables. (1) Nova Aql 1918 (V603 Aql) is declining at the rate of 0.44+-0.04 mag/century from 1938-2013. (2) Nova Cyg 1876 (Q Cyg) has been brightening at the rate of 0.41+-0.05 mag/century from 1891-2013. (3) Nova Aur 1964 (QZ Aur) faded from 1980-2009 at a rate of 1.5 mag/century. (4) QZ Aur had its orbital period get shorter by 0.00028. (5) For recurrent nova T CrB, my 110,000 magnitude light curve from 1855-2013 shows a unique and weird structure wherein the star was in a high state (1.5 mag brighter than the usual quiescence) from -8 to -1 year and +0.4 to +5 years, after both the 1866 and 1946 eruption. (5) I have measured changes in the orbital period across the eruptions of T CrB (1946), U Sco (1999 \& 2010), CI Aql (1946), and T Pyx (2011). All four recurrent novae ejected greatly more mass than they accreted in the prior inter-eruption time interval, so none of these recurrent nova can become Type Ia supernovae.