A Kinematical Detection of Two Embedded Jupiter-mass Planets in HD 163296

Abstract

We present the first kinematical detection of embedded protoplanets within a protoplanetary disk. Using archival ALMA observations of HD 163296, we demonstrate a new technique to measure the rotation curves of CO isotopologue emission to sub-percent precision relative to the Keplerian rotation. These rotation curves betray substantial deviations caused by local perturbations in the radial pressure gradient, likely driven by gaps carved in the gas surface density by Jupiter-mass planets. Comparison with hydrodynamic simulations shows excellent agreement with the gas rotation profile when the disk surface density is perturbed by two Jupiter mass planets at 83 au and 137 au. As the rotation of the gas is dependent on the pressure of the total gas component, this method provides a unique probe of the gas surface density profile without incurring significant uncertainties due to gas-to-dust ratios or local chemical abundances which plague other methods. Future analyses combining both methods promise to provide the most accurate and robust measures of embedded planetary mass. Furthermore, this method provides a unique opportunity to explore wide-separation planets beyond the mm continuum edge and to trace the gas pressure profile essential in modelling grain evolution in disks.

Importance of radiative effects in gap opening by planets in protoplanetary disks

“…Nevertheless, it would be interesting to include more planets and model the 10-200 au range of this system, assuming that each gap in dust continuum stems from a single planet opening a corresponding gap in gas density. This is further motivated by the kinematic detection of Jupiter-sized planets at 83 and 137 au by Teague et al (2018). We therefore carried out a simulation with three planets at 48, 86, and 145 au, respectively, and find similar results in the 10-50 au range.…”

Detectability of embedded protoplanets from hydrodynamical simulations

“…Observations in the dust continuum using ALMA (Isella et al 2016) confirmed the existence of three gaps at distances of ∼ 50, ∼ 81 and ∼ 136 AU (corrected with the new Gaia distance of 101.5 pc). Kinematical analysis of gas observations suggested the presence of two planets at the second and third gaps (Teague et al 2018). In Pinte et al (2018), HD models showed that a third planet is expected further out.…”

“…The DSHARP large program (Andrews et al 2018) has confirmed that substructure is ubiquitous in large discs when observed with enough resolution, although these disc features do not necessarily confirm the presence of planets. The first indirect detection of planets at these wavelengths was achieved from detailed analyses of the gas kinematics in the HD 163296 disc (Teague et al 2018;Pinte et al 2018).…”

Nine Localized Deviations from Keplerian Rotation in the DSHARP Circumstellar Disks: Kinematic Evidence for Protoplanets Carving the Gaps

“…The disturbed velocity pattern is detectable with high spectral and high spatial resolution ALMA line observations. Accurate measurements of rotation curves revealed for instance radial pressure gradients, likely driven by gaps carved in the gas surface density by Jupiter-mass planets in the disk of HD 163296 (Teague et al 2018a). In a given channel map, the emission is concentrated along the iso-velocity curve, i.e., the region of the disk where the projected velocity is constant.…”