Modeling Eclipses in the Classical Nova V Persei: The Role of the Accretion Disk Rim

Abstract

Multicolor (BVRI) light curves of the eclipsing classical nova V Per are presented, and a total of 12 new eclipse timings are measured for the system. When combined with previous eclipse timings from the literature, these timings yield a revised ephemeris for the times of mideclipse given by HJD = 2,447,442.8260(1) + 0.107123474(3)E. The eclipse profiles are analyzed with a parameter-fitting model that assumes four sources of luminosity: a white dwarf primary star, a main-sequence secondary star, a flared accretion disk with a rim, and a bright spot at the intersection of the mass transfer stream and the disk periphery. Model parameters include the temperatures of the white dwarf (T1) and the secondary star (T2), the radius (Rd) and temperature (Td), of the disk periphery, the inner disk radius (Rin), the disk power-law temperature exponent (α) and thickness (hr), and a bright spot temperature enhancement factor (χs). A matrix of model solutions are computed, covering an extensive range of plausible parameter values. The solution matrix is then explored to determine the optimum values for the fitting parameters and their associated errors. For models that treat the accretion disk as a flat structure without a rim, optimum fits require that the disk have a flat temperature profile. Although models with a truncated inner disk (Rin R1) result in a steeper temperature profile, steady state models with a temperature profile characterized by T(r) ∝ r-3/4 are found only for models with a significant disk rim. A comparison of the observed brightness and color at mideclipse with the photometric properties of the best-fitting model suggests that V Per lies at a distance of ~1 kpc.