Near-Infrared Monitoring and Modelling of V1647 Ori in its On-going 2008-12 Outburst Phase

Abstract

We present results of Mt Abu JHK photometric and HI Brackett \(\gamma\) line monitoring of the eruptive YSO V1647 Orionis (McNeil's Object) during the on-going outburst phase in 2008-2012. We discuss JHK colour patterns and extinction during the outburst and compare these with the previous outburst phase in 2004-05 and the intervening quiescent period of about 2 years. Commencing from early 2012, the object shows a slow fading out in all the bands. We report brightness variations in the nearby Herbig-Haro object HH22 possibly associated with those in V1647 Ori. We also present modelling of the spectral energy distributions of V1647 Ori during its recent outburst and quiescent phases. The physical parameters of the protostar and its circumstellar environment obtained from the modelling indicate marked differences in the two phases.