A multiwavelength light curve analysis of the classical nova V392 Per: Optical contribution from an irradiated accretion disk during the nova wind phase

Abstract

The classical nova V392 Per 2018 is characterized by a very fast optical decline, long binary orbital period of 3.23 days, detection of GeV gamma rays, and almost identical decay trends of $B$, $V$, and $I_{\rm C}$ light curves. The last feature is unique because most novae develop strong emission lines in the nebular phase and these lines contribute especially to the $B$ and $V$ bands and make large differences between the $BV$ and $I_{\rm C}$ light curves. This unique feature can be understood if the optical flux is dominated by continuum until the late phase of the nova outburst. Such continuum radiation is emitted by a bright accretion disk irradiated by a hydrogen burning white dwarf (WD) and viscous heating disk with high mass-accretion rate after the hydrogen burning ended. We present a comprehensive nova outburst model that reproduces all of these light curves. We determined the WD mass to be $M_{\rm WD}=1.35$ - $1.37 ~M_\odot$ and the distance modulus in the $V$ band to be $(m-M)_V=14.6 \pm 0.2$; the distance is $d= 3.45\pm 0.5$ kpc for the reddening of $E(B-V)=0.62$.