Simultaneous photometric and spectral analysis of a new outburst of V1686 Cyg

TL;DR

This paper reports on optical photometric and spectral observations of V1686 Cyg, revealing a significant outburst with a 3-magnitude brightness change over three months, and analyzes spectral variations correlated with brightness changes.

Contribution

It provides the first detailed photometric and spectral analysis of a new outburst in V1686 Cyg, linking spectral changes to brightness variations.

Findings

Brightness increased by nearly 3 magnitudes during the outburst.

The outburst lasted approximately 3 months.

Spectral features changed in correlation with photometric variations.

Abstract

We present an analysis of the optical observations of Herbig AeBe star V1686 Cyg, which is associated with a small isolated star-forming region around HAeBe star BD+40$^{\circ}$4124. We observed this star as a part of our project of young eruptive stars investigation. Observations were held on 2.6m telescope of Byurakan Observatory from 2015 to 2017. For this period we obtained V1686 Cyg direct images and 14 medium- and low-resolution spectra. In the course of observations we noticed that this star underwent a not-typical brightness outburst. After data reduction we found that the full rise and decline of V1686 Cyg brightness had almost 3 magnitudes amplitude and lasted about 3 months. We were also able to trace the changes of the stellar spectrum during the outburst, which are correlated with the photometric variations.