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Space Science Reviews

, Volume 66, Issue 1–4, pp 207–210 | Cite as

The atmospheric composition, extinction and luminosity of the LBV R71

  • D. J. Lennon
  • D. Wobig
  • R. -P. Kudritzki
  • O. Stahl
Massive Star Atmospheres and Stellar Winds

Abstract

ESO 3.6m Caspec spectra of the LMC luminous blue variable (LBV) taken at minimum have been analysed using NLTE model atmospheres and line formation calculations to derive atmospheric parameters and chemical composition. Using the silicon ionization balance and the hydrogen Balmer lines we deriveT eff =17250, log g=1.80 and a microturbulent velocity of 15–20 km/s. The analysis yields abundance ratios by number of approximately 0.43 for He/H, 0.03 for C/N and 0.14 for O/N, implying that enrichment of the atmosphere by processed material has taken place. We have re-evaluated the reddening of R71 using IUE low resolution data and published UBVRIJHKL photometry and derive a value for A V of 0.63. We also construct an extinction curve using archive IUE data for mid-B LMC supergiants and show that the extinction is anomalous; the 2175A bump being almost absent and the far UV rise very pronounced. A comparison of our model flux in theV-band with the observed (dereddened)V magnitude and the D.M. of the LMC (18.45), implies that the bolometric magnitude or R71 is −9.9. This is significantly higher than the value of −9.0 usually adopted for R71 and suggests that this object may not in fact be a ‘subluminous’ LBV.

Key words

stars:R71 stars:LBV stars:abundances stars:extinction 

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References

  1. Fitzpatrick, E.L.: 1991,PASP 103, 1123Google Scholar
  2. Roche, P.F., Aitken, D.K. and Smith, C.H.: 1993,MNRAS 262, 301Google Scholar
  3. Thackery, A.D.: 1974,MNRAS 168, 221Google Scholar
  4. Wolf, B., Appenzeller, I. and Stahl, O.: 1981,A&A 103, 94Google Scholar
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Copyright information

© Kluwer Academic Publishers 1994

Authors and Affiliations

  • D. J. Lennon
    • 1
  • D. Wobig
    • 1
  • R. -P. Kudritzki
    • 1
  • O. Stahl
    • 2
  1. 1.Universtatssternwarte MunchenMunchenFederal Republic of Germany
  2. 2.Landessternwarte KonigstuhlHeidelbergFederal Republic of Germany

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