Evidence for Residual Material in Accretion Disk Gaps: CO Fundamental Emission from the T Tauri Spectroscopic Binary DQ Tau

Abstract

We present the discovery of CO fundamental ro-vibrational emission from the classical T Tauri spectroscopic binary DQ Tau. The high-resolution infrared echelle spectra reveal emission lines from both the v=1 and v=2 vibrational levels with line widths of roughly 70 km/s. The average CO excitation temperature is approximately 1200 K. We model the spectra as arising from gas in Keplerian rotation about the center-of-mass of the binary. The disk model requires gas with an average surface density of 5 x 10-4 g cm-2 that extends outward to 0.5 +/- 0.1 AU and inward to at least 0.1 AU from the center-of-mass. The radial extent for the emitting gas is close to the predicted size of the gap in the DQ Tau accretion disk that is expected to be dynamically cleared by the binary. We interpret these results, and previous modeling of DQ Tau's spectral energy distribution, as evidence for a small amount (~ 1e-10 Msun) of diffuse material residing within the optically-thin disk gap. Thus dynamical clearing has not been completely efficient in the DQ Tau binary. We suggest that the material is associated with a flow from the circumbinary disk which feeds the ongoing accretion at the stellar surfaces.

to be published in The Astrophysical Journal

Cited by in corpus (31)

• Protoplanetary Disks and Their Evolution
• Observations of gas flows inside a protoplanetary gap
• The FUV spectrum of TW Hya. I. Observations of H${}_2$ Fluorescence
• The Nature of Transition Circumstellar Disks I. The Ophiuchus Molecular Cloud
• Hot H2O Emission and Evidence for Turbulence in the Disk of a Young Star
• Accretion in Evolved and Transitional Disks in Cep OB2: Looking for the Origin of the Inner Holes
• The Nature of Transition Circumstellar Disks II. Southern Molecular Clouds
• Modelling Circumbinary Gas Flows in Close T Tauri Binaries
• High Resolution 4.7 um Keck/NIRSPEC Spectra of Protostars. I: Ices and Infalling Gas in the Disk of L1489 IRS
• Scanning disk rings and winds in CO at 0.01-10 au: a high-resolution $M$-band spectroscopy survey with IRTF-iSHELL
• Looking for Pure Rotational H_2 Emission from Protoplanetary Disks
• The circumstellar environment of T Tau S at high spatial and spectral resolution
• Accretion and Magnetic Reconnection in the Classical T Tauri Binary DQ Tau
• The hybrid disks: a search and study to better understand evolution of disks
• Quiescent H2 Emission From Pre-Main Sequence Stars in Chamaeleon I
• High-Resolution Near Infrared Spectroscopy of HD 100546: II. Analysis of variable rovibrational CO emission lines
• Formation and Evolution of Planetary Systems: Upper Limits the Gas Mass in HD105
• CO Line Emission and Absorption from the HL Tau Disk: Where is all the dust?
• Dust Stratification in Young Circumstellar Disks
• Depletion of molecular gas by an accretion outburst in a protoplanetary disk
• Observational diagnostics of gas in protoplanetary disks
• Resolved observations of transition disks
• Anomalous Accretion Activity and the Spotted Nature of the DQ Tau Binary System
• Pre-main-sequence binaries with tidally disrupted discs: the Br gamma in HD 104237
• Interferometric Evidence for Resolved Warm Dust in the DQ Tau System
• A proposed new diagnostic for Herbig disc geometry: FWHM versus J of CO ro-vibrational lines
• The Inner Disk and Accretion Flow of the Close Binary DQ Tau
• Upper limits on CO 4.7 micron emission from disks around five Herbig Ae/Be stars
• Measuring Organic Molecular Emission in Disks with Low Resolution Spitzer Spectroscopy
• Spectroastrometric Study of Ro-vibrational CO Emission from the Herbig Ae star HD~179218 with iSHELL on the NASA Infrared Telescope Facility
• Axion-like Particles and their Possible Impact on the Very High-Energy Spectrum of M87 Observed by LHAASO