Intrinsic Reddening of Eta Carinae

Abstract

LAMBERT has pointed out a possible weakness in my derivation¹ of the total colour excess of Eta Carinae on the basis of [FeII] lines measured from photoelectric spectral scans by Aller², and has derived a higher value from a method which is undoubtedly sounder in principle. On the other hand, an inspection of Fig. 1 of my article¹ suggests that the errors resulting from the assumption that the lines which I used can be represented by an excitation temperature are not very large. A similar conclusion can be drawn from Lambert's figure, in which the reddening relation that he derives from a comparison of emission lines with the same upper level is evidently not very different from a least-squares line through all the points, even if the departures from a Boltzmann population that he finds among certain individual levels are real.