1999A&A...350.1007C


Query : 1999A&A...350.1007C

1999A&A...350.1007C - Astronomy and Astrophysics, volume 350, 1007-1017 (1999/10-3)

Wolf-Rayet nebulae as tracers of stellar ionizing fluxes. I. M 1-67.

CROWTHER P.A., PASQUALI A., DE MARCO O., SCHMUTZ W., HILLIER D.J. and DE KOTER A.

Abstract (from CDS):

We use WR124 (WN8h) and its associated nebula M 1-67, to test theoretical non-LTE models for Wolf-Rayet (WR) stars. Lyman continuum ionizing flux distributions derived from a stellar analysis of WR 124, are compared with nebular properties via photo-ionization modelling. Our study demonstrates the significant role that line blanketing plays in affecting the Lyman ionizing energy distribution of WR stars, of particular relevance to the study of HII regions containing young stellar populations. We confirm previous results that non-line blanketed WR energy distributions fail to explain the observed nebular properties of M 1-67, such that the predicted ionizing spectrum is too hard. A line blanketed analysis of WR 124 is carried out using the method of Hillier & Miller (1998ApJ...496..407H), with stellar properties in accord with previous results, except that the inclusion of clumping in the stellar wind reduces its wind performance factor to only ∼2. The ionizing spectrum of the line blanketed model is much softer than for a comparable temperature unblanketed case, such that negligible flux is emitted with energy above the HeI λ504 edge. Photo-ionization modelling, incorporating the observed radial density distribution for M 1-67 reveals excellent agreement with the observed nebular electron temperature, ionization balance and line strengths. An alternative stellar model of WR 124 is calculated, following the technique of de Koter et al. (1997ApJ...477..792D), augmented to include line blanketing following Schmutz et al. (1991ApJ...372..664S). Good consistency is reached regarding the stellar properties of WR 124, but agreement with the nebular properties of M 1-67 is somewhat poorer than for the Hillier & Miller code.

Abstract Copyright:

Journal keyword(s): stars: fundamental parameters - stars: individual: WR 124 - stars: Wolf-Rayet - ISM: HII regions - ISM: individual objects: M 1-67

Simbad objects: 6

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Number of rows : 6
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 HD 269227 WR* 05 13 54.2756276088 -69 31 46.665067440 11.429 11.98 11.918 12.13 10.557 WN9/10+M2Ia 156 0
2 HD 86161 WR* 09 54 52.9033957968 -57 43 38.274644604 7.94 8.65 8.36 8.93   WN8h 211 0
3 Hen 2-427 WR* 19 11 30.8749167768 +16 51 38.200938264   12.19 11.50     WN8h 328 0
4 HD 192163 WR* 20 12 06.5418877464 +38 21 17.784181008 7.12 7.49 7.50     WN6(h)-s 533 0
5 NGC 6888 ISM 20 12 07 +38 21.3   7.44       WN6b(h) 265 1
6 EM* AS 431 WR* 20 36 43.6322747712 +40 21 07.442607924     13.73 12.51   WN8(h)+B0.5V 215 0

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2022.06.30-15:38:58

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