Far Ultraviolet Spectral Analysis of the Prototype Nova-Like Variable VY Sculptoris from the High State to the Low State

TL;DR

This study analyzes the far-ultraviolet spectra of VY Sculptoris across different brightness states, revealing significant flux decline, accretion rate variations, and potential white dwarf detection.

Contribution

It provides detailed modeling of accretion disk and white dwarf atmospheres across multiple states, offering new insights into the system's behavior.

Findings

FUV flux declines by a factor of 28 from high to low state.

Accretion rates vary from 8e-9 to 1.9e-10 solar masses per year.

Possible detection of a 45,000K white dwarf in the low state spectrum.

Abstract

The prototype nova-like variable VY Sculptoris was observed by the IUE during four different optical brightness states of the system. The FUV flux level from the highest state to the lowest state declines by a factor of 28. We have carried out model accretion disk and white dwarf atmosphere fitting to the spectra. The corresponding accretion rates range from $\dot{M}= 8 \times 10^{-9}$M$_{\sun}$ yr$^{-1}$ at the highest FUV flux level down to $\dot{M}= 1.9\times 10^{-10}$M$_{\sun}$ yr$^{-1}$ at the lowest flux level. We report tentative evidence for the detection of the underlying white dwarf with $T_{\rm eff} = 45,000$K in the spectrum with the lowest flux level.