相关论文: Wolf-Rayet Central Stars of Planetary Nebulae: The…

We analyse the impact that spatial resolution has on the inferred numbers and types of Wolf-Rayet (WR) and other massive stars in external galaxies. Continuum and line images of the nearby galaxy M33 are increasingly blurred to mimic…

We report the first-ever discovery of an extragalactic Wolf-Rayet (WR)star with Spitzer. A new WR star in the Large Magellanic Cloud (LMC) was revealed via detection of its circumstellar shell using 24 {\mu}m images obtained in the…

Aims: Following our comprehensive studies of the WR stars in the Milky Way, we now present spectroscopic analyses of almost all known WN stars in the LMC. Methods: For the quantitative analysis of the wind-dominated emission-line spectra,…

Context. There are more than 3000 known Galactic planetary nebulae (PNe), but only 492 central stars of Galactic planetary nebulae (CSPN) have known spectral types. It is vital to increase this number in order to have reliable statistics,…

We report the detection of WC stars in 5 Wolf-Rayet (WR) galaxies: He 2-10, NGC 3049, NGC 3125, NGC 5253 and Tol 89. The faint broad CIV5808 line requires sufficiently high S/N to be detected explaining the non-detection of this WC feature…

The numbers and types of evolved massive stars found in nearby galaxies provide an exacting test of stellar evolution models. Because of their proximity and rich massive star populations, the Magellanic Clouds have long served as the…

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…

We report the serendipitous discovery of a ring nebula around a candidate Wolf-Rayet (WR) star, HBHA 4202-22, in Cygnus using the Spitzer Space Telescope archival data. Our spectroscopic follow-up observations confirmed the WR nature of…

We present a VLT/FORS1 survey of Wolf-Rayet (WR) stars in the spiral galaxy NGC 1313. In total, 94 WR candidate sources have been identified from narrow-band imaging. Of these, 82 have been spectroscopically observed, for which WR emission…

(Abridged) We have performed a comprehensive multiwavelength analysis of a sample of 20 starburst galaxies that show the presence of a substantial population of massive stars. The main aims are the study of the massive star formation and…

Expansion velocities (Vexp) of different ions and line widths at the base of the lines are measured and analyzed for 24 PNe with [WC]-type nuclei (WRPNe), 9 PNe ionized by WELS (WLPNe) and 14 ordinary PNe. A comparative study of the…

The structure and evolution of central stars of planetary nebulae (CSPNe) is reviewed. CSPNe represent the rapid transitional stage between the Asymptotic Giant Branch (AGB) and the white-dwarf domain. It is shown that the whole evolution…

As part of a search for Wolf-Rayet (WR) stars in the Magellanic Clouds, we have discovered a new type of WR star in the Large Magellanic Cloud (LMC). These stars have both strong emission lines, as well as He ii and Balmer absorption lines…

Only a handful of binary central stars of planetary nebulae (PNe) are known today, due to the difficulty of detecting their companions. Preliminary results from radial velocity surveys, however, seem to indicate that binarity plays a…

Most population I Wolf-Rayet (WR) stars are the He-rich descendants of the most massive stars (M_i = 25 - 100 M_sun). Evidence has been accumulating over the years that among all pop I WR stars, those of the relatively cool, N-rich subtype…

Most massive stars reside in multiple systems that will interact over the course of their lifetime. Classical Wolf-Rayet (WR) stars represent the final end stages of stellar evolution at the upper-mass end. As part of a homogeneous,…

We present a multi-wavelength characterisation of the planetary nebula (PN) NGC 6905 and its [Wolf-Rayet]-type ([WR]) central star (CSPN) HD 193949. Our Nordic Optical Telescope (NOT) Alhambra Faint Object Spectrograph and Camera (ALFOSC)…

Wolf-Rayet (WR) galaxies are a rare population of galaxies that host living high-mass stars during their WR phase (i.e. WR stars) and are thus expected to provide interesting constraints on the stellar Initial Mass Function, massive star…

The central star (CSPN) of the planetary nebula M 1-25 (PN G 4.9+4.9) is classified as a [WC 6] star, the only CSPN of this subclass known at this time. A comparison with the other emission-lines CSPN (the [WC]-class and the 'weak…

Wolf-Rayet (WR) stars are evolved massive stars with strong fast stellar winds. WR stars in our Galaxy have shown three possible sources of X-ray emission associated with their winds: shocks in the winds, colliding stellar winds, and…