Interferometric observations of V1663 Aquilae (nova AQL 2005)

We have resolved the classical nova V1663 Aql using long-baseline near-IR interferometry covering the period from ∼5 to 18 days after peak brightness. We directly measure the shape and size of the fireball, which we find to be asymmetric. In addition, we measure an apparent expansion rate of 0.21 ± 0.03 mas day^-1. Assuming a linear expansion model, we infer a time of initial outburst approximately 4 days prior to peak brightness. When combined with published spectroscopic expansion velocities, our angular expansion rate implies a distance of 8.9 ± 3.6 kpc. This distance measurement is independent of, but consistent with, determinations made using widely available photometric relations for novae.