HST and Optical Data on SDSSJ0804+5103 (EZ Lyn) One Year after Outburst

TL;DR

This study presents ultraviolet and optical observations of the cataclysmic variable EZ Lyn one year after outburst, revealing stable periodic signals and spectral characteristics of the white dwarf, contributing to understanding post-outburst behavior.

Contribution

First detailed UV and optical spectral analysis of EZ Lyn post-outburst, identifying stable periodicities and white dwarf properties over an extended timescale.

Findings

Detected a stable 256 sec period in UV and optical light curves.

White dwarf characterized as 13,100K with solar-like composition.

Long-term stability of the 256 sec period over several months.

Abstract

We present an ultraviolet spectrum and light curve of the short orbital period cataclysmic variable EZ Lyn obtained with the Cosmic Origins Spectrograph on the Hubble Space Telescope 14 months after its dwarf nova outburst, along with ground-based optical photometry. The UV spectrum can be fit with a 13,100K, log g=8 white dwarf using 0.5 solar composition, while fits to the individual lines are consistent with solar abundance for Si and Al, but only 0.3 solar for C. The Discrete Fourier Transforms of the UV and optical light curves at 14 months following outburst show a prominent period at 256 sec. This is the same period reported by Pavlenko in optical data obtained 7 months and one year after outburst, indicating its long term stability over several months, but this period is not evident in the pre-outburst data and is much shorter than the 12.6 min period that was seen in observations obtained during an interval from 8 months to 2.5 years after the 2006 outburst. In some respects, the long and short periods are similar to the behavior seen in GW Lib after its outburst but the detailed explanation for the appearance and disappearance of these periods and their relation to non-radial pulsation modes remain to be explored with theoretical models.