Research Papers in Physics and Astronomy


Date of this Version


Document Type



The Astrophysical Journal, 419:L21-L24, 1993 December 10.


Copyright 1993 The American Astronomical Society. All rights reserved.


Recently, the Cepheids in the spiral galaxy IC 4182 have been in the spotlight due to their use as calibrators for the supernova Ia distance scale. In this process the distance to IC 4182 is obtained by applying the local Population I period-luminosity relation to the IC 4182 Cepheid sample. But is it really appropriate to do so? We employ the technique of Fourier decomposition to compare the light curves of long-period Cepheids in IC 4182 with those of their Population I counterparts in the Galaxy. At the level of precision of the current data, no Difference is apparent between the two groups. On the other hand, both groups have light curves which seem distinct from those of a number of Population II Cepheids in the Galaxy. Accordingly, we find no reason why the local period-luminosity relation should not be used to infer the distance to IC 4182.