# V1647 Orionis: Optical Photometric and Spectroscopic Monitoring Through the 2003-2006 Outburst

## TL;DR

This study monitored V1647 Orionis over two years, revealing its outburst lasted about 27 months with significant spectral and brightness changes, providing insights into early low-mass star formation.

## Contribution

It offers detailed optical photometric and spectroscopic data on V1647 Orionis's outburst, enhancing understanding of eruptive young stars' behavior.

## Key findings

- Outburst duration was approximately 27 months.
- V1647 Ori's brightness remained near peak then faded by 5 magnitudes.
- Spectral features showed significant variability during the outburst.

## Abstract

We present results from an optical imaging and spectroscopic monitoring campaign on the young, low-mass eruptive variable star V1647 Orionis. The star and associated nebulosity (McNeil's Nebula) were observed over the period February 2004 to February 2006 with observations commencing a few months after the original outburst event occurred. Using the Gemini North telescope, we obtained multi-band optical imaging photometry and medium-resolution long-slit spectroscopy of V1647 Ori on an approximately monthly interval. During this period, V1647 Ori remained at, or close to, peak brightness and then faded by 5 magnitudes to close to its pre-outburst brightness. This implies an outburst timescale of around 27 months. Spectral features seen in both emission and absorption varied considerably during the monitoring period. For example, the Halpha line changed significantly in both intensity and profile. We present and discuss the observed photometric and spectroscopic changes and consider how this eruptive event relates to the early formative stages of low-mass stars.