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

Abstract

We analysed UV FUSE, IUE, and HST/STIS spectra of five of the hottest [WCE]-type central stars of planetary nebulae: NGC 2867, NGC 5189, NGC 6905, Pb 6, and Sand 3. The analysis leveraged on our grid of CMFGEN synthetic spectra, which covers the parameter regime of hydrogen deficient central stars of planetary nebulae and allows a uniform and systematic study of the stellar spectra. The stellar atmosphere models calculated by us include many elements and ionic species neglected in previous analyses, which allowed us to improve the fits to the observed spectra considerably and provided an additional diagnostic line: the Ne VII $\lambda$ 973 $\mathring{\mathrm{A}}$, which had not been modelled in [WCE] spectra and which presents, in these stars, a strong P-Cygni profile. We report newly derived photospheric and wind parameters and elemental abundances. The central stars of NGC 2867, NGC 5189, and Pb 6 had their temperatures revised upward in comparison with previous investigations and we found the carbon to helium mass ratio of the sample objects to span a wide range of values, 0.42$\le$C:He$\le$1.96. Modelling of the Ne VII $\lambda$ 973 $\mathring{\mathrm{A}}$ P-Cygni profile indicated strong neon overabundances for the central stars of NGC 2867, NGC 5189, NGC 6905, and Pb 6, with Ne mass fractions between 0.01 and 0.04. Nitrogen abundances derived by us for the central stars of NGC 5189, Pb 6, and Sand 3 are higher than previous determinations by factors of 3, 10, and 14, respectively.

arXiv commentAccepted on MNRAS

References in corpus (25)

• Overview of the Far Ultraviolet Spectroscopic Explorer Mission
• Evolutionary and pulsational properties of white dwarf stars
• The Element Abundances in Bare Planetary Nebula Central Stars and the Shell Burning in AGB Stars
• The formation and evolution of hydrogen-deficient post-AGB white dwarfs: the emerging chemical profile and the expectations for the PG1159-DB-DQ evolutionary connection
• Neglecting the porosity of hot-star winds can lead to underestimating mass-loss rates
• Evolution on the AGB and beyond: On the formation of H-deficient post-AGB stars
• The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale
• Full evolutionary models for PG1159 stars. Implications for the helium-rich O(He) stars
• Clumping in the inner winds of hot, massive stars from hydrodynamical line-driven instability simulations
• 2D Simulations of the Line-Driven Instability in Hot-Star Winds: II. Approximations for the 2D Radiation Force
• Central Stars of Planetary Nebulae: New spectral classifications and catalogue
• Angular dimensions of planetary nebulae
• Galactic planetary nebulae with Wolf-Rayet nuclei. II. A consistent observational data set
• Identification of neon in FUSE and VLT spectra of extremely hot hydrogen-deficient (pre-) white dwarfs
• Detailed Far-UV to Optical Analysis of Four [WR] Stars
• Far-UV Spectroscopic Analyses of Four Central Stars of Planetary Nebulae
• Central Stars of Planetary Nebulae in the Large Magellanic Cloud: A Far-UV Spectroscopic Analysis
• Sulfur, Chlorine, & Argon Abundances in Planetary Nebulae. IIB: Abundances in a Southern Sample
• Abell 48 - a rare WN-type central star of a planetary nebula
• Sulfur, Chlorine, and Argon in Planetary Nebulae. IIA: Observations of a Southern Sample
• Discovery of NeVII in the Winds of Hot Evolved Stars
• Iron abundance in the prototype PG1159 star, GW Vir pulsator PG1159-035, and related objects
• The Ultraviolet Spectra of the Weak Emission Line Central Stars of Planetary Nebulae
• A New Grid of Synthetic Spectra for the Analysis of [WC]-type Central Stars of Planetary Nebulae
• Galactic kinematics of planetary nebulae with [WC] central star

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• Catalogue of central stars of planetary nebulae: Expanded edition
• A radial velocity survey for post-common-envelope Wolf-Rayet central stars of planetary nebulae: First results and discovery of the close binary nucleus of NGC 5189
• C/O ratios in planetary nebulae with dual-dust chemistry from faint optical recombination lines
• Co-spatial Long-slit UV/Optical Spectra of Ten Galactic Planetary Nebulae with HST/STIS I. Description of the Observations, Global Emission-line Measurements, and CNO Abundances
• Properties of central stars of planetary nebulae with distances in Gaia DR2
• Mapping Excitation in the Inner Regions of the Planetary Nebula NGC 5189 using HST WFC3 Imaging
• Co-spatial Long-slit UV/Optical Spectra of Ten Galactic Planetary Nebulae with HST/STIS II. Nebular Models, Central Star Properties and He+CNO Synthesis
• Hot bubbles of planetary nebulae with hydrogen-deficient winds - II. Analytical approximations with application to BD+30${}^{\circ }$3639
• WR 72: a born-again planetary nebula with hydrogen-poor knots
• A carbon-rich hot bubble in the planetary nebula NGC 5189
• Planetary nebulae with Wolf-Rayet-type central stars -- IV. NGC 1501 and its mixing layer
• Catching a grown-up starfish planetary nebula II. Plasma analysis and central star properties of PC 22
• Planetary nebulae with Wolf-Rayet-type central stars -- III. A detailed view of NGC 6905 and its central star
• Hot bubbles of planetary nebulae with hydrogen-deficient winds. III. Formation and evolution in comparison with hydrogen-rich bubbles
• Planetary Nebulae in the eROSITA eRASS1 catalog