TheHubbleSpaceTelescopeKey Project on the Extragalactic Distance Scale. XIII. The Metallicity Dependence of the Cepheid Distance Scale
Year: 1998
Type: article
Abstract: Uncertainty in the metal-abundance dependence of the Cepheid variable period-luminosity (PL) relation remains one of the outstanding sources of systematic error in the extragalactic distance scale and in the Hubble constant. To test for such a metallicity dependence, we have used the Wide Field Planetary Camera 2 (WFPC2) on the Hubble Space Telescope ( HST ) to observe Cepheids that span a range in oxygen abundance of 0.7 ± 0.15 dex in two fields in the nearby spiral galaxy M101. A differential analysis of the PL relations in V and I in the two fields yields a marginally significant change in the inferred distance modulus on metal abundance, with δ( m - M ) 0 /δ[O/H] = -0.24 ± 0.16 mag dex -1 . The trend is in the theoretically predicted sense that metal-rich Cepheids appear brighter and closer than metal-poor stars. External comparisons of Cepheid distances with those derived from three other distance indicators, in particular from the tip of the red giant branch method, further constrain the magnitude of any Z -dependence of the PL relation at V and I . The overall effects of any metallicity dependence on the distance scale derived with HST will be of the order of a few percent or less for most applications, though distances to individual galaxies at the extremes of the metal abundance range may be affected at the 10% level.
Source: The Astrophysical Journal
DOI: 10.1086/305538
Authors: Robert C. Kennicutt, Jr., Peter B. Stetson, Abhijit Saha, Dan Kelson, Daya M. Rawson, Shoko Sakai, Barry F. Madore, Jeremy R. Mould, Wendy L. Freedman, Fabio Bresolin, Laura Ferrarese, Holland Ford, Brad K. Gibson, John A. Graham, Mingsheng Han, Paul Harding, John G. Hoessel, John P. Huchra, Shaun M. G. Hughes, Garth D. Illingworth, Lucas M. Macri, Randy L. Phelps, Nancy A. Silbermann, Anne M. Turner, Peter R. Wood
Institutions: University of Arizona, Dominion Astrophysical Observatory, Space Telescope Science Institute, University of California, Santa Cruz, Australian National University, Mount Stromlo Observatory, California Institute of Technology, Infrared Processing and Analysis Center, Carnegie Observatories, Johns Hopkins University, Carnegie Institution for Science, Department of Terrestrial Magnetism, University of Wisconsin–Madison, Center for Astrophysics Harvard & Smithsonian, Royal Observatory in Greenwich
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2063867934