High Resolution Optical and NIR Spectra of HBC 722

Abstract

We present the results of high resolution (R$\ge$30,000) optical and near-IR spectroscopic monitoring observations of HBC 722, a recent FU Orionis object that underwent an accretion burst in 2010. We observed HBC 722 in optical/near-IR with the BOES, HET-HRS, and IGRINS spectrographs, at various points in the outburst. We found atomic lines with strongly blueshifted absorption features or P Cygni profiles, both evidence of a wind driven by the accretion. Some lines show a broad double-peaked absorption feature, evidence of disk rotation. However, the wind-driven and disk-driven spectroscopic features are anti-correlated in time; the disk features became strong as the wind features disappeared. This anti-correlation might indicate that the rebuilding of the inner disk was interrupted by the wind pressure during the first two years. The Half-Width at Half-Depth (HWHD) of the double-peaked profiles decreases with wavelength, indicative of the Keplerian rotation; the optical spectra with the disk feature are fitted by a G5 template stellar spectrum convolved with a rotation velocity of 70 km s${}^{-1}$ while the near-IR disk features are fitted by a K5 template stellar spectrum convolved with a rotation velocity of 50 km s${}^{-1}$. Therefore, the optical and near-IR spectra seem to trace the disk at 39 and 76 ${\text{R}}_{\odot }$, respectively. We fit a power-law temperature distribution in the disk, finding an index of 0.8, comparable to optically thick accretion disk models.

22 pages, 5 figures, accepted for publication in ApJ

References in corpus (5)

• The Hot Inner Disk of FU Ori
• The Differential Rotation of FU Ori
• Line Structure in the Spectrum of FU Orionis
• X-ray emission from an FU Ori star in early outburst: HBC 722
• Color Variability of HBC 722 in the Post-Outburst Phases

Cited by in corpus (7)

• Multi-wavelength study of the low-luminosity outbursting young star HBC 722
• Diagnosing FUor-like Sources: The Parameter Space of Viscously Heated Disks in the Optical and Near-IR
• High-resolution spectroscopic monitoring observations of FU Orionis-type object, V960 Mon
• Ice features of low-luminosity protostars in near-infrared spectra of AKARI/IRC
• The FUor star V2493 Cyg (HBC 722) -- eleven years at maximum brightness
• A study of the photometric and spectroscopic variations of the prototypical FU Orionis-type star V1057 Cyg
• Evidence of Accretion Burst: The Viscously Heated Inner Disk of the Embedded Protostar IRAS 16316-1540