2009AJ....137.2968A

We present new Keck II NIRSPEC high-spectral resolution 2 µm echelle observations of the young eruptive variable star V1647 Orionis. This star went into outburst in late 2003 and faded to its pre-outburst brightness after approximately 26 months. V1647 Orionis is the illuminating star of McNeil's Nebula and is located near M 78 in the Lynds 1630 dark cloud. Our spectra have a resolving power of approximately 18,000 and allow us to study in detail the weak absorption features present on the strong near-IR veiled continuum. An analysis of the echelle orders containing Mg I (2.1066 µm) and Al I (2.1099 µm), Brγ (2.1661 µm), the Na I doublet (2.206 and 2.209 µm), and the CO overtone bandhead (2.2935 µm) gives us considerable information on the physical and geometric characteristics of the regions producing these spectral features. We find that, at high spectral resolution, V1647 Orionis in quiescence resembles a significant number of FU Orionis type eruptive variables and does not appear similar to the quiescent EX Lupi variables observed. This correspondence is discussed and implications for the evolutionary state of the star are considered.