Spectroscopic Study of the Envelope of the Hybrid Nova V458 Vul and Surrounding Nebula

TL;DR

This study presents spectroscopic analysis of the hybrid nova V458 Vul, revealing cyclic variations, elemental abundances exceeding solar levels, and detailed physical conditions of the surrounding nebula.

Contribution

It provides the first detailed spectroscopic measurements of the nova's envelope and surrounding nebula, including elemental abundances, temperature, and density estimates, with observed cyclic variations.

Findings

Detected short- and long-period profile variations in forbidden [FeVII] lines.

Estimated elemental abundances exceeding solar values by factors of 4.4 to 4.8.

Determined electron temperatures and densities for nebular knots.

Abstract

Spectroscopic observations of the hybrid V458 Vul obtained between days 9 and 778 after the brightness maximum are analyzed. Short-period, daily profile variations of forbidden [FeVII] iron lines were detected in the nebular phase, as well as a long-period (about 60-day) cyclic variation that was correlated with the photometric and X-ray cycles. The abundances of helium, neon, and iron in the nova's envelope have been estimated. The helium, neon, and iron abundances exceed the solar values by factors of 4.4, 4.8, and 3.7. The envelope mass is 1.4$\times$ 10$^{-5}$M$_{\odot}$. The electron temperatures and number densities have been calculated for the Northwestern and Southeastern knots of the planetary nebula. The temperature derived for the Northwestern knot is Te = 10 000 K and the electron number density, n$_{e}$ = 600 cm $^{-3}$ for the Southeastern knot, Te = 13 000 K and n$_{e}$ = 750 cm$^{-3}$.