An Outburst Detected in the Spectrum of HD 6226

Abstract

HD 6226 is a bright binary Be star at visual magnitude 6.81 (Hipparcos database). The emission and absorption phases occur in cycles, which are probably not periodic. The suspected period of about 630 days (derived from photometric measurements) is not confirmed by our spectroscopic survey. The latest emission phase developed in the beginning of 2003, then the emission strength systematically decreased and disappeared between July 21, 2003 and August 4, 2003. The last (absorption) spectrum was exposed on August 25, 2003. Unexpected very strong emission appeared in a spectrum exposed on October 28, 2003. A short-term photometric brightening followed this “outburst”.

Long-term spectroscopic RV studies revealed a 2.615 d period modulated by a 29.7 d period (in the He I 6678 line), which perhaps may be interpreted as orbital period of a binary. Nevertheless, the physical nature of the dominant short 2.615 d period is not yet clear.

The last detected emission episode has changed considerably our view of the interesting object HD 6226. We hope this study will reveal more details of the physical properties of the Be phenomenon.