2019ApJS..242...18H

We obtained the absolute magnitudes, distances, and white dwarf (WD) masses of 32 recent galactic novae based on the time-stretching method for nova light curves. A large part of the light/color curves of two classical novae often overlap each other if we properly squeeze/stretch their timescales. Then, a target nova brightness is related to the other template nova brightness by (M_V[t])_template=(M_V[t/f_s]-2.5logf_s)_target, where t is the time, M_V[t] is the absolute V magnitude, and f_s is their timescaling ratio. Moreover, when these two time-stretched light curves, (t/f_s)-(M_V - 2.5 log f_s), overlap each other, (t/f_s)-(B - V)₀ do too, where (B - V)₀ is the intrinsic B - V color. Thus, the two nova tracks overlap each other in the (B - V)₀-(M_V - 2.5 log f_s) diagram. Inversely, using these properties, we obtain/confirm the distance and reddening by comparing each nova light/color curves with well-calibrated template novae. We classify the 32 novae into two types, LV Vul and V1500 Cyg, in the time-stretched (B - V)₀-(M_V - 2.5 log f_s) color-magnitude diagram. The WD mass is obtained by direct comparison of the model V light curves with the observation. Thus, we obtain a uniform set of 32 galactic classical novae that provides the distances and WD masses from a single method. Many novae broadly follow the universal decline law and the present method can be applied to them, while some novae largely deviate from the universal decline law and so the method cannot be directly applied to them. We discuss such examples.