Spectral analysis of BD+30$^{\circ}$623, the peculiar binary central star of the planetary nebula NGC 1514

TL;DR

This paper conducts a detailed spectral analysis of the binary central star of planetary nebula NGC 1514, accurately determining parameters of both stars for the first time using optical and ultraviolet spectra.

Contribution

It provides the first precise spectroscopic parameters for both stars in the binary system of NGC 1514's central star.

Findings

Cool star: T_eff = 9850±150 K, log g = 3.50±0.25

Hot companion: T_eff between 80000 K and 95000 K, log g ≈ 5.5

Parameters determined using composite grid and minimum χ² fitting

Abstract

NGC 1514 is a complex planetary nebula with a peculiar binary central star (BD+30$^{\circ}$623) consisting of a cool star and a hot companion. To date, the parameters of the two stars have not been firmly stablished. We present a detailed spectral analysis of BD+30$^{\circ}$623 based on intermediate-resolution CAFOS optical spectra and IUE ultraviolet spectra with the goal of deriving the parameters of the two stars. For this purpose, we used an extensive composite grid of Kurucz and T\"ubingen NLTE Model-Atmosphere spectra. From the fitting procedure, in terms of the minimum $\chi^{2}$ method, the best models obtained correspond to an Horizontal-Branch A0 star with $T_{\rm eff}$ = 9850$\pm$150 K, log g = 3.50$\pm$0.25, and a hot companion with $T_{\rm eff}$ between 80000 K and 95000K and a log g $\simeq$ 5.5. To our knowledge, this is the first time that the parameters of both stars have been determined accurately through a detailed spectroscopic analysis.