The Hubble Space Telescope Extragalactic Distance Scale Key Project. X. The Cepheid Distance to NGC 7331

H0 Key Project; :; Shaun M. G. Hughes; Mingsheng Han; John Hoessel; Wendy L. Freedman; Robert C. Kennicutt; Jeremy. R. Mould; Abi Saha; Peter B. Stetson; Barry F. Madore; Nancy A. Silbermann; Paul Harding; Laura Ferrarese; Holland Ford; Brad K. Gibson; John A. Graham; Robert Hill; John Huchra; Garth D. Illingworth; Randy Phelps; Shoko Sakai

doi:10.1086/305808

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The Hubble Space Telescope Extragalactic Distance Scale Key Project. X. The Cepheid Distance to NGC 7331

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Abstract

The distance to NGC 7331 has been derived from Cepheid variables observed with HST/WFPC2, as part of the Extragalactic Distance Scale Key Project. Multi-epoch exposures in F555W (V) and F814W (I), with photometry derived independently from DoPHOT and DAOPHOT/ALLFRAME programs, were used to detect a total of 13 reliable Cepheids, with periods between 11 and 42 days. The relative distance moduli between NGC 7331 and the LMC, imply an extinction to NGC 7331 of A_V = 0.47+-0.15 mag, and an extinction-corrected distance modulus to NGC 7331 of 30.89+-0.14(random) mag, equivalent to a distance of 15.1 Mpc. There are additional systematic uncertainties in the distance modulus of +-0.12 mag due to the calibration of the Cepheid Period-Luminosity relation, and a systematic offset of +0.05+-0.04 mag if we applied the metallicity correction inferred from the M101 results of Kennicutt et al 1998.

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H0 Key Project, :, Shaun M. G. Hughes, Mingsheng Han, John Hoessel, Wendy L. Freedman, Robert C. Kennicutt, Jeremy. R. Mould, Abi Saha, Peter B. Stetson, Barry F. Madore, Nancy A. Silbermann, Paul Harding, Laura Ferrarese, Holland Ford, Brad K. Gibson, John A. Graham, Robert Hill, John Huchra, Garth D. Illingworth, Randy Phelps, Shoko Sakai. 1998-02-13. The Hubble Space Telescope Extragalactic Distance Scale Key Project. X. The Cepheid Distance to NGC 7331. https://doi.org/10.1086/305808

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