Spectro-astrometric imaging of molecular gas within protoplanetary disk gaps

Abstract

We present velocity-resolved spectro-astrometric imaging of the 4.7 $\mu$m rovibrational lines of CO gas in protoplanetary disks using the CRIRES high resolution infrared spectrometer on the Very Large Telescope (VLT). The method as applied to three disks with known dust gaps or inner holes out to 4-45 AU (SR 21, HD 135344B and TW Hya) achieves an unprecedented spatial resolution of $0.1-0.5$ AU. While one possible gap formation mechanism is dynamical clearing by giant planets, other equally good explanations (stellar companions, grain growth, photo-evaporation) exist. One way of distinguishing between different scenarios is the presence and distribution of gas inside the dust gaps. Keplerian disk models are fit to the spectro-astrometric position-velocity curves to derive geometrical parameters of the molecular gas. We determine the position angles and inclinations of the inner disks with accuracies as good as 1-2\degr, as well as the radial extent of the gas emission. Molecular gas is detected well inside the dust gaps in all three disks. The gas emission extends to within a radius of 0.5 AU for HD 135344B and to 0.1 AU for TW Hya, supporting partial clearing by a $<1-10M_{\mathrm{Jup}}$ planetary body as the cause of the observed dust gaps, or removal of the dust by extensive grain coagulation and planetesimal formation. The molecular gas emission in SR 21 appears to be truncated within $\sim 7$AU, which may be caused by complete dynamical clearing by a more massive companion. We find a smaller inclination angle of the inner disk of TW Hya than that determined for the outer disk, suggestive of a disk warp. We also detect significant azimuthal asymmetries in the SR 21 and HD 135344B inner disks.

7 pages, accepted for publication in ApJ

References in corpus (8)

• Accretion Rates in Herbig Ae stars
• H2O and OH gas in the terrestrial planet-forming zones of protoplanetary disks
• Dust dynamics during protoplanetary disc clearing
• Demographics of Transition Objects
• The Disk Around CoKu Tau/4: Circumbinary, not Transitional
• HST/ACS Multiband Coronagraphic Imaging of the Debris Disk around Beta Pictoris
• High spatial resolution mid-infrared observations of the low-mass young star TW Hya
• Modeling the gas-phase chemistry of the transitional disk around HD 141569A

Cited by in corpus (55)

• Protoplanetary Disk Structures in Ophiuchus
• Astrochemistry and compositions of planetary systems
• LkH$\alpha$ 330: Evidence for dust clearing through resolved submillimeter imaging
• Protoplanetary disk masses from CO isotopologues line emission
• Gas density drops inside dust cavities of transitional disks around young stars observed with ALMA
• On the gas content of transitional disks: a VLT/X-Shooter study of accretion and winds
• Tracing Slow Winds from T Tauri Stars via Low Velocity Forbidden Line Emission
• Can grain growth explain transition disks?
• On the origin of horseshoes in transitional discs
• On the diversity of asymmetries in gapped protoplanetary disks
• Tracing the inner edge of the disk around HD 100546 with Ro-vibrational CO Emission Lines
• Hints for icy pebble migration feeding an oxygen-rich chemistry in the inner planet-forming region of disks
• Gas and dust structures in protoplanetary disks hosting multiple planets
• The depletion of water during dispersal of planet-forming disk regions
• High-precision C17O, C18O and C16O measurements in young stellar objects: analogues for CO self-shielding in the early solar system
• Vortices and spirals in the HD135344B transition disk
• Vacuum-UV spectroscopy of interstellar ice analogs. II. Absorption cross-sections of nonpolar ice molecules
• Polycyclic Aromatic Hydrocarbon in Protoplanetary Disks around Herbig Ae/Be and T Tauri Stars
• Scanning disk rings and winds in CO at 0.01-10 au: a high-resolution $M$-band spectroscopy survey with IRTF-iSHELL
• Scattered light shadows in warped protoplanetary discs
• The structure of disks around Herbig Ae/Be stars as traced by CO ro-vibrational emission
• Constraining the structure of the transition disk HD 135344B (SAO 206462) by simultaneous modeling of multiwavelength gas and dust observations
• The diverse chemistry of protoplanetary disks as revealed by JWST
• Wind-driven Accretion in Transitional Protostellar Disks
• Transition disks: the observational revolution from SEDs to imaging
• JWST Observations of Young protoStars (JOYS): overview of program and early results
• Measuring protoplanetary disk gas surface density profiles with ALMA
• Exploring the link between star and planet formation with Ariel
• CO depletion: a microscopic perspective
• A gas density drop in the inner 6 AU of the transition disk around the Herbig Ae star HD 139614: Further evidence for a giant planet inside the disk?
• Circumstellar disks and planets. Science cases for next-generation optical/infrared long-baseline interferometers
• A "Rosetta Stone" for protoplanetary disks: The synergy of multi-wavelength observations
• The 1600 Angstrom Emission Bump in Protoplanetary Disks: A Spectral Signature of H${}_2$O Dissociation
• The dry and carbon poor inner disk of TW Hya: evidence for a massive icy dust trap
• The chemistry of planet-forming regions is not interstellar
• The nitrogen carrier in protoplanetary disks
• ALMA Band 6 high-resolution observations of the transitional disk around SY Cha
• New insights on the near-infrared veiling of young stars using CFHT/SPIRou data
• Density and infrared band strength of interstellar carbon monoxide (CO) ice analogues
• Spatially Resolving the Kinematics of the <100 μas Quasar Broad Line Region using Spectroastrometry
• Near Infrared High Resolution Spectroscopy and Spectro-astrometry of Gas in Disks around Herbig Ae/Be Stars
• A survey for variable young stars with small telescopes: II -- Mapping a protoplanetary disk with stable structures at 0.15 AU
• Asymmetric fundamental band CO lines as a sign of an embedded giant planet
• Residual Gas & Dust Around Transition Objects and Weak T Tauri Stars
• Signatures of Hot Molecular Hydrogen Absorption from Protoplanetary Disks: I. Non-thermal Populations
• UV Fluorescence Traces Gas and LyA Evolution in Protoplanetary Disks
• Spectroastrometric Reverberation Mapping of Broad-line Regions
• Modeling of CO ro-vibrational line emission of HD 141569
• CRIRES-VLT high-resolution spectro-astrometry as a tool in the search of small structures at the cores of Planetary Nebulae
• Detection of H${}_2$ in the TWA 7 System: A Probable Circumstellar Origin
• Evidence of a Disk-wind Origin for Fluorescent H${}_2$ in Classical T Tauri Stars
• Molecules with ALMA at Planet-forming Scales (MAPS). XV. Tracing protoplanetary disk structure within 20 au
• Efficient computational methods for rovibrational transition rates in molecular collisions
• Protoplanetary Disk Chemistry
• Gas chemistry in the dust depleted inner regions of protoplanetary disks. I. Near-IR spectra and overtones