A New Grid of Synthetic Spectra for the Analysis of [WC]-type Central Stars of Planetary Nebulae

Abstract

We present a comprehensive grid of synthetic stellar-atmosphere spectra, suitable for the analysis of high resolution spectra of hydrogen-deficient post-Asymptotic Giant Branch (post-AGB) objects hotter than 50000 K, migrating along the constant luminosity branch of the Hertzsprung-Russell diagram (HRD). The grid was calculated with CMFGEN, a state-of-the-art stellar atmosphere code that properly treats the stellar winds, accounting for expanding atmospheres in non-LTE, line blanketing, soft X-rays, and wind clumping. We include many ionic species that have been previously neglected. Our uniform set of models fills a niche in an important parameter regime, i.e., high effective temperatures, high surface gravities, and a range of mass-loss values. The grid constitutes a general tool to facilitate determination of the stellar parameters and line identifications and to interpret morphological changes of the stellar spectrum as stars evolve through the central star of planetary nebula (CSPN) phase. We show the effect of major physical parameters on spectral lines in the far-UV, UV, and optical regimes. We analyse UV and far-UV spectra of the central star of NGC 6905 using the grid to constrain its physical parameters, and proceed to further explore other parameters not taken in consideration in the grid. This application shows that the grid can be used to constrain the main photospheric and wind parameters, as a first step towards a detailed analysis. The full grid of synthetic spectra, comprising far-UV, UV, optical, and IR spectral regions, is available on-line.

References in corpus (6)

• A Grid of NLTE Line-Blanketed Model Atmospheres of Early B-type Stars
• Neglecting the porosity of hot-star winds can lead to underestimating mass-loss rates
• The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale
• Statistical Properties of the GALEX/SDSS matched source catalogs, and classification of the UV sources
• Detailed Far-UV to Optical Analysis of Four [WR] Stars
• Discovery of photospheric argon in very hot central stars of planetary nebulae and white dwarfs

Cited by in corpus (4)

• UV spectral analysis of very hot H-deficient [WCE]-type central stars of planetary nebulae: NGC 2867, NGC 5189, NGC 6905, Pb 6, and Sand 3
• Catalog of Planetary Nebulae detected by GALEX and corollary optical surveys
• Hot Stars in the GALEX Ultraviolet Sky Surveys (GUVcat_AISxSDSS_HS) and the Binary Fraction of Hot Evolved Stars
• Planetary nebulae with Wolf-Rayet-type central stars -- III. A detailed view of NGC 6905 and its central star