Last gasp of V1647 Ori: a brief post-outburst warm, molecular wind

摘要

Followup infrared spectroscopy is reported for V1647 Ori, a young star whose re-cent eruption illuminated McNeil's Nebula. Lines of H_I,H_2, and CO are compared to previousobservations. We find that the accretion rate fell two orders of magnitude and the CO band-heads disappeared at the end of the outburst. We also report a striking metamorphosis of thefundamental CO spectrum from centrally peaked profiles to emission lines with superimposedblue-shifted absorption lines and back again one year later. This remarkable change in spec-tral appearance indicates that the system did not return to equilibrium immediately followingthe outburst. In this paper we propose a mechanism to explain the emergence of a transientpost-outburst outflow.