High-resolution Spectroscopic Monitoring Observations of FU Orionis–type Object, V960 Mon

Abstract

We present the results of high-resolution ( R  ≥ 30,000) optical and near-infrared (NIR) spectroscopic monitoring observations of an FU Orionis–type object (FUor), V960 Mon, which underwent an outburst in 2014 November. We have monitored this object with the Bohyunsan Optical Echelle Spectrograph and the Immersion GRating INfrared Spectrograph since 2014 December. Various features produced by a wind, disk, and outflow/jet were detected. The wind features varied over time and continually weakened after the outburst. We detected double-peaked line profiles in the optical and NIR, and the line widths tend to decrease with increasing wavelength, indicative of Keplerian disk rotation. The disk features in the optical and NIR spectra fit well with G-type and K-type stellar spectra convolved with a kernel to account for the maximum projected disk rotation velocities of about 40.3 ± 3.8 km s −1 and 36.3 ± 3.9 km s −1 , respectively. We also report the detection of [S ii ] and H 2  emission lines, which are jet/outflow tracers and rarely found in FUors.