Revealing the spectroscopic variations of FU Orionis object V960 Mon with high-resolution spectroscopy

Abstract

We present the results of the high-resolution spectroscopy of the FU Orionis-type star V960 Mon. The brightness of V960 Mon decreased continuously after the outburst was detected in 2014 November. During this dimming event, we have carried out medium-resolution spectroscopic monitoring observations and found that the equivalent width of the absorption features showed variations. To further investigate the spectroscopic variations, we conducted a high-resolution spectroscopic observation of V960 Mon with the Subaru Telescope and the High Dispersion Spectrograph on 2018 January 8 and 2020 February 1. By comparing this spectrum with the archival data of the Keck Observatory and the High Resolution Echelle Spectrometer taken between 2014 and 2017, we found that the absorption profiles changed as V960 Mon faded. The line profile of absorption lines such as Fe I and Ca I can be explained by a sum of the spectra of the disk atmosphere and the central star. The model spectrum created to explain the variations of the line profiles suggests that the effective temperature of the central star is $\sim$5500 K, which is comparable to that of the pre-outburst phase with a distance of 1.6 kpc with Gaia. The spectrum also shows that the effective temperature of the disk atmosphere decreased as V960 Mon faded. The variations of the H$\alpha$ and Ca II lines (8498.0 A, 8542.1 A) also show that the V960 Mon spectrum became central-star dominant.

arXiv comment16 pages, 11 figures, accepted for publication in ApJ

References in corpus (15)

• Gaia Data Release 2. Summary of the contents and survey properties
• The Gaia mission
• Evidence for a T Tauri Phase in Young Brown Dwarfs
• A Near-IR Spectroscopic Survey of FU Orionis Objects
• Evidence for an FU Orionis-like Outburst from a Classical T Tauri Star
• Evidence for J and H-band excess in classical T Tauri stars and the implications for disk structure and estimated ages
• The image slicer for the Subaru Telescope High Dispersion Spectrograph
• The Periodic Spectroscopic Variability of FU Orionis
• Line Structure in the Spectrum of FU Orionis
• Resolving the Sub-AU-Scale Gas and Dust Distribution in FU Orionis Sources
• The progenitor of the FUor-type young eruptive star 2MASS J06593158-0405277
• High Resolution Optical and NIR Spectra of HBC 722
• Light curves of the latest FUor: Indication of a close binary
• Age Determination Method of Pre-Main Sequence Stars with High-Resolution I-Band Spectroscopy
• The Spectroscopic Variations of the FU Orionis Object V960 Mon

Cited by in corpus (3)

• The FUor star V2493 Cyg (HBC 722) -- eleven years at maximum brightness
• Protostellar Outflows: a window to the past
• Spectroscopy of 9 eruptive young variables using TANSPEC