Interstellar extinction in the Large Magellanic Cloud

A systematic investigation of interstellar extinction in the ultraviolet as a function of position in the Large Magellanic Cloud has been made from an enlarged sample of reddened and comparison stars distributed throughout the cloud. Except for one star SK-69-108, the most reddened star of our sample, the shape of the extinction curves for the LMC stars do not show significant variations. All curves show an increase in extinction towards 2200 Å, but some have maxima near 2200 Å, some near 1900 Å. It has been shown that the feature of the extinction curve near 1900 Å is caused by the mismatch of the stellar F III 1920 Å feature. The strength of this 1920 Å feature as a function of luminosity and spectral type has been determined. The extinction curves have been corrected for the mismatch of the 1920 feature and a single mean extinction curve for the LMC normalized to |$A_V=0$| and |$E_{B-V}=1$| is presented. For the same value of |$E_{B-V}$| the LMC stars show the 2200 Å feature weaker by a factor 2 as compared with the galactic stars. Higher extinction shortward of 2000 Å in the LMC extinction curves than that in our Galaxy, as reported in earlier papers, is confirmed. The intrinsic colours |$(m_\lambda-V)_0$| of the luminous cloud members as a function of spectral type have been derived, using the mean extinction law for the LMC.

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