The Rapid Formation of Coronal Lines in the Nova V1674 Herculis

Abstract The nova V1674 Her (Nova Her 2021) has been reported to have the shortest interval between outburst and coronal line formation of any nova yet observed. We present optical and near-infrared spectroscopy from three epochs ranging from shortly before coronal line formation to shortly after. Taken together with the published results of Woodward et al., they indicate that not only did the coronal lines form very early in the nova’s development, but in going from undetectable to detectable in two days, and undetectable to significant, in six days, they developed very rapidly as well.