V1647 Orionis: Reinvigorated Accretion and the Re-Appearance of McNeil's Nebula

TL;DR

This paper reports on a new outburst of V1647 Orionis in 2008, detailing its photometric and spectroscopic properties, and compares it to the star's previous 2003 eruption, revealing reinvigorated accretion activity.

Contribution

It provides the first detailed observations of the 2008 outburst of V1647 Orionis and compares it to the 2003 event, highlighting changes in spectral features and accretion behavior.

Findings

Star brightened again to previous maximum levels.

Spectroscopy shows a P Cygni profile in Halpha with high-velocity absorption.

Near-infrared spectra indicate weaker CO absorption and stronger water vapor absorption.

Abstract

In late 2003, the young eruptive variable star V1647 Orionis optically brightened by over 5 magnitudes, stayed bright for around 26 months, and then decline to its pre-outburst level. In August 2008 the star was reported to have unexpectedly brightened yet again and we herein present the first detailed observations of this new outburst. Photometrically, the star is now as bright as it ever was following the 2003 eruption. Spectroscopically, a pronounced P Cygni profile is again seen in Halpha with an absorption trough extending to -700 km/s. In the near-infrared, the spectrum now possesses very weak CO overtone bandhead absorption in contrast to the strong bandhead emission seen soon after the 2003 event. Water vapor absorption is also much stronger than previously seen. We discuss the current outburst below and relate it to the earlier event.