相关论文: [WN] central stars of planetary nebulae

A considerable fraction of the central stars of planetary nebulae (CSPNe) are hydrogen-deficient. Almost all of these H-deficient central stars (CSs) display spectra with strong carbon and helium lines. Most of them exhibit emission line…

We report on the serendipitous discovery of the first central star of a planetary nebula (PN) that mimics the helium- and nitrogen-rich WN sequence of massive Wolf-Rayet (WR) stars. The central star of IC 4663 (PN G346.2-08.2) is dominated…

Several [WC]-type central stars of planetary nebulae (PNe) are known to mimic the spectroscopic appearance of massive carbon-rich or WC-type Wolf-Rayet stars. In stark contrast, no [WN]-type central stars have yet been identified as…

Hydrogen-deficient central stars of planetary nebula such as Wolf-Rayet and PG1159 central stars and some weak emission line stars are primarily composed of helium and carbon. This abundance is well explained by a scenario where a single…

A considerable fraction of the central stars of planetary nebulae (CSPNe) are hydrogen-deficient. As a rule, these CSPNe exhibit a chemical composition of helium, carbon, and oxygen with the majority showing Wolf-Rayet-like emission line…

[WC]-type CSPNs are hydrogen-deficient Central Stars of Planetary Nebulae showing strong stellar winds and a carbon-rich chemistry. We have analyzed new high-resolution spectra of [WC]-type CSPNs with the Potsdam Wolf-Rayet (PoWR) non-LTE…

Wolf-Rayet (WR) stars comprise a class of stars whose spectra are dominated by strong, broad emission lines that are associated with copious mass loss. In the massive-star regime, roughly 90% of the known WR stars are thought to have…

Wolf-Rayet (WR) stars are massive stars that have lost most or all of their hydrogen via powerful stellar winds. Recent observations have indicated that hydrogen-free WR stars have cooler temperatures than those predicted by current…

Over a hundred planetary nebulae (PNe) are known to have H-deficient central stars that mimic the spectroscopic appearance of massive Wolf-Rayet stars. The formation of these low-mass Wolf-Rayet stars, denoted [WR] stars, remains poorly…

We review the properties of carbon-sequence ([WC]) Wolf-Rayet central stars of planetary nebulae (CSPNe). Differences between the subtype distribution of [WC] stars and their massive WC cousins are discussed. We conclude that [WO]-type…

Over the past decade, the number of planetary nebula central stars (CSPN) known to exhibit the Wolf-Rayet (WR) phenomenon has grown substantially. Many of these discoveries have resulted from the Macquarie/AAO/Strasbourg Ha (MASH) PN…

Aims: Chemical compositions and other properties of planetary nebulae around central stars of spectral types [WC], [WO], and wels are compared with those of `normal' central stars, in order to clarify the evolutionary status of each type…

This paper is focused on the transition phase between central stars and white dwarfs, i.e. objects in the effective temperature range 100,000 - 200,000 K. We confine our review to hydrogen-deficient stars because the common H-rich objects…

The final explosive fate of massive stars, and the nature of the compact remnants they leave behind (black holes and neutron stars), are major open questions in astrophysics. Many massive stars are stripped of their outer hydrogen envelopes…

Wolf-Rayet (WR) stars are the evolved descendants of the most massive stars and show emission-line dominated spectra formed in their powerful stellar winds. Marking the final evolution stage before core collapse, the standard picture of WR…

We present high resolution spectrophotometric data for 34 galactic planetary nebulae with [WC] nuclei (WRPNe).The sample includes PNe with early and late [WC] stars and some WELS. Physical conditions and chemical abundances have been…

Wolf-Rayet ([WR]) and weak emission-line ($wels$) central stars of planetary nebulae (PNe) have hydrogen-deficient atmospheres, whose origins are not well understood. In the present study, we have conducted plasma diagnostics and abundance…

The striking broad emission line spectroscopic appearance of Wolf-Rayet (WR) stars has long defied analysis, due to the extreme physical conditions within their line and continuum forming regions. Recently, model atmosphere studies have…

Massive Wolf-Rayet (WR) stars comprise a spectroscopic class characterized by high temperatures (Teff > ~30 kK) and powerful and rapid stellar winds. Hydrogen-rich WR stars represent the most massive stars in existence (M > ~100 Msun),…

A number of late [WC] stars have unique infrared properties, not found among the non-[WC] planetary nebulae, and together define a class of IR-[WC] stars. They have unusual IRAS colours, resembling stars in the earliest post-AGB evolution…