# Studying Spectral Behavior, Accretion Processes and Photometric Behavior of Some Binary Stars in the Ultraviolet and Optical Regions

## TL;DR

This paper analyzes the spectral and photometric evolution of three classical novae in ultraviolet and optical regions, linking spectral behavior to envelope properties and comparing observations with theoretical models.

## Contribution

It provides a detailed study of spectral and photometric changes in classical novae, correlating spectral lines with envelope conditions and validating theoretical models.

## Key findings

- Spectral line fluxes vary with envelope optical thickness and temperature.
- Optical light curves show distinct maxima and minima at different times.
- Results align with existing theoretical models of nova outbursts.

## Abstract

We study the evolution of the normalized flux of selected ultraviolet emission lines of three classical novae (PW Vul, V1668 Cyg and V1974 Cyg). Different phases ofthe outbursts are studied. We attribute the spectral behavior of the three systems to the variation of the optical thickness and temperature of the envelope during the different phases of the outbursts. Our results are consistent with the theoretical models of classical novae. We also present optical photometric observations of the three systems in the post-novae phase. These observations show the variation of the light curves of these systems and the different times of maxima and minima.