Emission Line Profile Variations in the Early Coronal Phase of the Nova V2944 Ophiuchi

Abstract

V2944 Ophiuchi was a Fe ii type novae that reached moderate excitation and displayed large variations among the profiles of its emission lines. The profiles become increasingly double-peaked as the ionization level of the parent ion increases. At the extremes, H i and O i have flat-topped profiles while the coronal features [Si vii] and [Ca viii] peak in the line wings and have centers that fall to near the continuum level. He ii, N v, and [Si vi] display intermediate behavior but in the same sense that the line center depth is smallest for He ii and largest for [Si vi. A possible explanation for these profile variations is that the emission line region is ring-like in structure and becomes increasingly flattened as line excitation increases.