New eruptive variable in the massive star-forming region associated with IRAS 18507+0121

Byurakan Astrophysical Observatory, 0213 Aragatsotn Prov., Armenia
e-mail: elena@bao.sci.am

Received: 28 July 2016
Accepted: 24 March 2017

Abstract

Aims. We report the discovery of a strong outburst of the embedded young stellar object (YSO) UKIDSS−J185318.36+012454.5, located in the star-forming region associated with IRAS 18507+0121 and the ultra-compact H II region GAL 034.4+00.23.

Methods. Using archival photometric data and images, we determined the amplitude and the epoch of the outburst as well as the evolution stage and the basic parameters of the object.

Results. According to the near- and mid-infrared colors and spectral energy distribution, we classify the object as an intermediate-mass YSO with Class 0/I evolution stage. The outburst apparently started between May 2003 and April 2004. The amplitude of the outburst is at least ΔK_s = 5.0 mag. The summation of the photometric and spectral data does not allow classifying UKIDSS−J185318.36+012454.5 as an FU Orionis (FUor) or EX Orionis (EXor) object. We can consider it as an eruptive variable with mixed characteristics or as an MNor type object.