Final Report

Crowther, J. G.

doi:10.1007/978-1-349-01670-9_25

Cited by 62 publications

(170 citation statements)

References 7 publications

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“…According to the stellar parameters derived by Crowther & Smith (1997) and Pasquali et al (1997), Ofpe/WN9 and WN9-11 stars have effective temperatures in the range between 21 000 K and 35 000 K. Therefore, IRAS 18576+0341 may be hotter than 15 000 ± 9000 K as estimated by Ueta et al (2001).…”

Section: Ir Spectroscopymentioning

confidence: 94%

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IRAS 18576+0341: A new addition to the class of Galactic Luminous Blue Variables

Pasquali¹,

Comerón²

2002

A&A

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Section: Ir Spectroscopymentioning

confidence: 94%

“…Ofpe/WN9 stars (Bohannan & Walborn 1989, recently re-classified as WN9-11 by Crowther & Smith 1997) are generally believed to be quiescent LBVs (Pasquali et al 1997): AG Carinae is the typical example of an LBV whose spectrum shows the Ofpe/WN9 morphology when the star is at its minimum, hence at its maximum T eff (cf. Stahl 1987).…”

Section: Ir Spectroscopymentioning

confidence: 99%

IRAS 18576+0341: A new addition to the class of Galactic Luminous Blue Variables

Pasquali¹,

Comerón²

2002

A&A

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“…Indeed, there are no cases for which FWHM (C  λ5808) ≥ 100 Å, corresponding to WO subtypes in the Milky Way/LMC (Kingsburgh et al 1995;Drew et al 2004), Group galaxies are marked, populations have been divided into WNE and WNL subtypes. Data for Galactic and LMC WNL stars are taken from Crowther & Smith (1997), WNE information can be found in Conti & Massey (1989). except possibly #6 for which no evidence of O  λ3811-34 is observed.…”

Section: Properties Of Wr Stars At High Metallicitymentioning

confidence: 99%

A spectroscopic search for the non-nuclear Wolf-Rayet population of the metal-rich spiral galaxy M 83

Hadfield

Crowther

Schild

et al. 2005

A&A

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Abstract. We present a catalogue of non-nuclear regions containing Wolf-Rayet stars in the metal-rich spiral galaxy M 83 (NGC 5236). From a total of 283 candidate regions identified using He  λ4686 imaging with VLT-FORS2, Multi Object Spectroscopy of 198 regions was carried out, confirming 132 WR sources. From this sub-sample, an exceptional content of ∼1035 ± 300 WR stars is inferred, with N(WC)/N(WN) ∼ 1.2, continuing the trend to larger values at higher metallicity amongst Local Group galaxies, and greatly exceeding current evolutionary predictions at high metallicity. Late-type stars dominate the WC population of M 83, with N(WC8-9)/N(WC4-7) = 9 and WO subtypes absent, consistent with metallicity dependent WC winds. Equal numbers of late to early WN stars are observed, again in contrast to current evolutionary predictions. Several sources contain large numbers of WR stars. In particular, #74 (alias region 35 from de Vaucouleurs et al.) contains ∼230 WR stars, and is identified as a Super Star Cluster from inspection of archival HST/ACS images. Omitting this starburst cluster would result in revised statistics of N(WC)/N(WN) ∼ 1 and N(WC8-9)/N(WC4-7) ∼ 6 for the "quiescent" disk population. Including recent results for the nucleus and accounting for incompleteness in our spectroscopic sample, we suspect the total WR population of M 83 may exceed 3000 stars.

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“…Little reddening and a radial velocity of v rad = 118 km s −1 supports S 119 not being a member of the main body of the LMC. The main stellar parameters of S 119 have been determined by Crowther & Smith (1997) using two different models to account for the contamination of the nebula in the stellar spectrum: T eff = 26 200/27 000 K, L = 5.8 × 10 5 /6.3 × 10 5 L , anḋ M = 1.34 × 10 −5 /1.20 × 10 −5 M yr −1 .…”

Section: Introductionmentioning

confidence: 99%

An outflow from the nebula around the LBV candidate S 119

Weis

Duschl

Bomans

2003

A&A

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Abstract.We present an analysis of the kinematic and morphological structure of the nebula around the LMC LBV candidate S 119. On HST images, we find a predominantly spherical nebula which, however, seems to be much better confined in its eastern hemisphere than in the western one. The filamentary western part of the nebula is indicative of matter flowing out of the nebula's main body. This outflow is evidenced by our long-slit echelle spectra. They show that, while most of the nebula has an expansion velocity of 25.5 km s −1 , the outflowing material reaches velocities of almost 140 km s −1 , relative to the systemic one. A ROSAT HRI image shows no trace of S 119 and thus no indications of hot or shocked material.Key words. stars: evolution -stars: individual: S 119 -stars: mass-loss -ISM: bubbles -ISM: jets and outflows IntroductionStars with masses in the range of 50−100 M and luminosities of 10 5 −10 6 L populate the upper left end of the Hertzsprung-Russell Diagram (HRD). During their short lives of < ∼ 10 7 yrs they evolve from hot O stars on the main sequence towards cooler temperatures, first at almost constant luminosities. They soon enter a phase of very strong mass loss of up to 10 −4 M yr −1 . This influences their further evolution dramatically: They do not evolve further towards lower temperatures, i.e., towards the red supergiant state, but rather turn in the HRD and become hotter again, albeit later less luminous (e.g., Schaller et al. 1992;Langer et al. 1994).The region in the HRD where this turn occurs is known to be the domain of the Luminous Blue Variables (LBVs). There exists an empirical limit that separates a region in the HRD into which the most massive stars do not evolve, the so-called Humphreys-Davidson Limit (Humphreys & Davidson 1979. Here the stars not only exhibit large continuous mass loss, but at least some of them undergo giant eruptions. Both, the continuous wind and the eruptions lead to a peeling off of the outer parts of the stellar envelope and to the formation of circumstellar LBV nebulae (LBVN; e.g., Nota et al. 1995). Humphreys & Davidson (1994) Bohannan & Walborn (1989). Since the early eighties, there was already the suspicion of a close relation between Ofpe/WN9 stars and LBVs when R127, located again in the LMC and previously classified as Ofpe/WN9 underwent an LBV outburst (Stahl et al. 1983). The evidence for a connection between the two stellar classes has become even stronger since then, as longtime spectroscopic monitoring of LBVs and Ofpe/WN9 stars became available (see, e.g., Stahl & Wolf 1986;Wolf et al. 1988;Bohannan & Walborn 1989;Nota et al. 1996;Pasquali et al. 1996).After discovering a nebula around S 119, Nota et al. (1994) classified the star as an LBV candidate. Their ESO New Technology Telescope (NTT) image shows a nebula of 7 × 9 size (corresponding to 1.9 pc × 2.1 pc for an assumed distance of the LMC of 51.2 kpc), with a brighter lobe. Their NTT/EMMI spectra indicate an expansion velocity of the S 119 nebula of ∼25 km s −1 , and a ratio of H α /N ...

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Final Report

Cited by 62 publications

References 7 publications

IRAS 18576+0341: A new addition to the class of Galactic Luminous Blue Variables

IRAS 18576+0341: A new addition to the class of Galactic Luminous Blue Variables

A spectroscopic search for the non-nuclear Wolf-Rayet population of the metal-rich spiral galaxy M 83

An outflow from the nebula around the LBV candidate S 119

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