The distance to Supernova 1998aq in NGC 3982

The distance to NGC 3982, host galaxy to the Type Ia supernova SN 1998aq, is derived using 32 Cepheids discovered in archival multi-epoch Hubble Space Telescope observations. Employing recent Large Magellanic Cloud Cepheid period–luminosity relations and absolute zero-point, we find a distance to NGC 3982 of $20.5 \pm 0.8 (r) \pm 1.7 (s) \mathrm {Mpc}$, including both random (r) and systematic (s) uncertainties, and ignoring any metallicity dependence in the Cepheid period–luminosity relation. Still unpublished light curve photometry promises to make SN 1998aq one of the most important calibrators for the Type Ia supernova decline rate–peak luminosity relationship.