Asymmetric fundamental band CO lines as a sign of an embedded giant planet

Abstract

We investigate the formation of double-peaked asymmetric line profiles of CO in the fundamental band spectra emitted by young (1-5Myr) protoplanetary disks hosted by a 0.5-2 Solar mass star. Distortions of the line profiles can be caused by the gravitational perturbation of an embedded giant planet with q=4.7 10^-3 stellar-to-planet mass ratio. Locally isothermal, 2D hydrodynamic simulations show that the disk becomes globally eccentric inside the planetary orbit with stationary ~0.2-0.25 average eccentricity after ~2000 orbital periods. For orbital distances 1-10 AU, the disk eccentricity is peaked inside the region where the fundamental band of CO is thermal excitated. Hence, these lines become a sensitive indicators of the embedded planet via their asymmetries (both in flux and wavelength). We find that the line shape distortions (e.g. distance, central dip, asymmetry and positions of peaks) of a given transition depend on the excitation energy (i.e. on the rotational quantum number J). The magnitude of line asymmetry is increasing/decreasing with J if the planet orbits inside/outside the CO excitation zone (R_CO<=3, 5 and 7 AU for a 0.5,1 and 2 Solar mass star, respectively), thus one can constrain the orbital distance of a giant planet by determining the slope of peak asymmetry-J profile. We conclude that the presented spectroscopic phenomenon can be used to test the predictions of planet formation theories by pushing the age limits for detecting the youngest planetary systems.

arXiv comment7 pages, 5 figures, to appear in ApJL

References in corpus (26)

• Spectral Energy Distributions of T Tauri Stars With Passive Circumstellar Disks
• Models of Giant Planet formation with migration and disc evolution
• FARGO: a fast eulerian transport algorithm for differentially rotating disks
• Spitzer Space Telescope study of disks in the young $\sigma$ Orionis cluster
• A comparative study of disc-planet interaction
• Models of Jupiter's Growth Incorporating Thermal and Hydrodynamic Constraints
• Star and protoplanetary disk properties in Orion's suburbs
• Spectro-astrometric imaging of molecular gas within protoplanetary disk gaps
• Disk eccentricity and embedded planets
• CO emission from discs around isolated HAeBe and Vega-excess stars
• Formation of Jupiter using opacities based on detailed grain physics
• Possible planet-forming regions on submillimetre images
• VLT-CRIRES Survey of Rovibrational CO Emission from Protoplanetary Disks
• Circumstellar Disks in the IC 348 Cluster
• Planetesimal and gas dynamics in binaries
• Simulations of eccentric disks in close binary systems
• Circumstellar disks in binary star systems
• Planet Formation in Binary Stars: The case of Gamma Cephei
• Gaps in Protoplanetary Disks as Signatures of Planets: I. Methodology and Validation
• On the eccentricity of self-gravitating circumstellar disks in eccentric binary systems
• Eccentricity of radiative discs in close binary-star systems
• Trapping of giant-planet cores - I. Vortex aided trapping at the outer dead zone edge
• Spectral signatures of disk eccentricity in young binary systems: I. Circumprimary case
• Three-dimensional modeling of radiative disks in binaries
• Low-mass planets in nearly inviscid disks: Numerical treatment
• Detectability of giant planets in protoplanetary disks by CO emission lines

Cited by in corpus (10)

• Gas and dust structures in protoplanetary disks hosting multiple planets
• The Structure of Pre-transitional Protoplanetary Disks. II. Azimuthal Asymmetries, Different Radial Distributions of Large and Small Dust Grains in PDS~70
• The circumstellar disk response to the motion of the host star
• 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?
• Vortex Formation and Evolution in Planet Harboring Disks under Thermal Relaxation
• Interpreting Brightness Asymmetries in Transition Disks: Vortex at Dead Zone or Planet Carved Gap Edges?
• Nonlinear hydrodynamical evolution of eccentric Keplerian discs in two dimensions: validation of secular theory
• An unusual reservoir of water emission in the VV CrA A protoplanetary disk
• Origin of Ca II emission around polluted white dwarfs
• Planet Formation Imager (PFI): science vision and key requirements