Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Meridional flows in the disk around a young star


Protoplanetary disks are known to possess a variety of substructures in the distribution of their millimetre-sized grains, predominantly seen as rings and gaps1, which are frequently interpreted as arising from the shepherding of large grains by either hidden, still-forming planets within the disk2 or (magneto-)hydrodynamic instabilities3. The velocity structure of the gas offers a unique probe of both the underlying mechanisms driving the evolution of the disk—such as movement of planet-building material from volatile-rich regions to the chemically inert midplane—and the details of the required removal of angular momentum. Here we report radial profiles of the three velocity components of gas in the upper layers of the disk of the young star HD 163296, as traced by emission from 12CO molecules. These velocities reveal substantial flows from the surface of the disk towards its midplane at the radial locations of gaps that have been argued to be opened by embedded planets4,5,6,7: these flows bear a striking resemblance to meridional flows, long predicted to occur during the early stages of planet formation8,9,10,11,12. In addition, a persistent radial outflow is seen at the outer edge of the disk that is potentially the base of a wind associated with previously detected extended emission12.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Rotation maps and the inferred 3D geometry of the disk.
Fig. 2: Measured velocity structure of the gas in the disk around HD 163296.
Fig. 3: Schematic of the meridional flow.
Fig. 4: Hydrodynamical simulations of meridional flows.

Similar content being viewed by others

Data availability

This paper makes use of the following ALMA data: ADS/JAO.ALMA#2013.1.00366.S, ADS/JAO.ALMA#2013.1.00601.S and ADS/JAO.ALMA#2016.1.00484.L. The raw data are available from the ALMA archive (, while the imaged data and scripts are available from the DSHARP website ( The Python packages used for the analysis of the data are available via their GitHub repositories: bettermoments ( and eddy (


  1. Andrews, S. M. et al. The Disk Substructures at High Angular Resolution Project (DSHARP). I. Motivation, sample, calibration, and overview. Astrophys. J. 869, L41 (2018).

    Article  ADS  CAS  Google Scholar 

  2. Zhang, S. et al. The Disk Substructures at High Angular Resolution Project (DSHARP). VII. The planet–disk interactions interpretation. Astrophys. J. 869, L47 (2018).

    Article  ADS  Google Scholar 

  3. Flock, M. et al. Gaps, rings, and non-axisymmetric structures in protoplanetary disks. From simulations to ALMA observations. Astron. Astrophys. 574, A68 (2015).

    Article  Google Scholar 

  4. Isella, A. et al. Ringed structures of the HD 163296 protoplanetary disk revealed by ALMA. Phys. Rev. Lett. 117, 251101 (2016).

    Article  ADS  Google Scholar 

  5. Isella, A. et al. The Disk Substructures at High Angular Resolution Project (DSHARP). IX. A high-definition study of the HD 163296 planet-forming disk. Astrophys. J. 869, L49 (2018).

    Article  ADS  CAS  Google Scholar 

  6. Teague, R., Bae, J., Bergin, E. A., Birnstiel, T. & Foreman-Mackey, D. A kinematical detection of two embedded Jupiter-mass planets in HD 163296. Astrophys. J. 860, L12 (2018).

    Article  ADS  Google Scholar 

  7. Pinte, C. et al. Kinematic evidence for an embedded protoplanet in a circumstellar disk. Astrophys. J. 860, L13 (2018).

    Article  ADS  Google Scholar 

  8. Szulágyi, J., Morbidelli, A., Crida, A. & Masset, F. Accretion of Jupiter-mass planets in the limit of vanishing viscosity. Astrophys. J. 782, 65 (2014).

    Article  ADS  Google Scholar 

  9. Morbidelli, A. et al. Meridional circulation of gas into gaps opened by giant planets in three-dimensional low-viscosity disks. Icarus 232, 266–270 (2014).

    Article  ADS  Google Scholar 

  10. Fung, J. & Chiang, E. Gap opening in 3D: single-planet gaps. Astrophys. J. 832, 105 (2016).

    Article  ADS  Google Scholar 

  11. Dong, R., Liu, S.-Y. & Fung, J. Observational signatures of planets in protoplanetary disks: planet-induced line broadening in gaps. Astrophys. J. 870, 72 (2019).

    Article  ADS  CAS  Google Scholar 

  12. Klaassen, P. D. et al. ALMA detection of the rotating molecular disk wind from the young star HD 163296. Astron. Astrophys. 555, A73 (2013).

    Article  Google Scholar 

  13. Flaherty, K. M. et al. Weak turbulence in the HD 163296 protoplanetary disk revealed by ALMA CO observations. Astrophys. J. 813, 99 (2015).

    Article  ADS  Google Scholar 

  14. Rosenfeld, K. A., Andrews, S. M., Hughes, A. M., Wilner, D. J. & Qi, C. A spatially resolved vertical temperature gradient in the HD 163296 disk. Astrophys. J. 774, 16 (2013).

    Article  ADS  CAS  Google Scholar 

  15. Pinte, C. et al. Direct mapping of the temperature and velocity gradients in discs. Imaging the vertical CO snow line around IM Lupi. Astron. Astrophys. 609, A47 (2018).

    Article  Google Scholar 

  16. Teague, R., Bae, J., Birnstiel, T. & Bergin, E. A. Evidence for a vertical dependence on the pressure structure in AS 209. Astrophys. J. 868, 113 (2018).

    Article  ADS  CAS  Google Scholar 

  17. Kley, W., D’Angelo, G. & Henning, T. Three-dimensional simulations of a planet embedded in a protoplanetary disk. Astrophys. J. 547, 457–464 (2001).

    Article  ADS  Google Scholar 

  18. Lin, D. N. C. & Papaloizou, J. On the tidal interaction between protoplanets and the protoplanetary disk. III – Orbital migration of protoplanets. Astrophys. J. 309, 846–857 (1986).

    Article  ADS  Google Scholar 

  19. Flaherty, K. M. et al. A Three-dimensional view of turbulence: constraints on turbulent motions in the HD 163296 protoplanetary disk using DCO+. Astrophys. J. 843, 150 (2017).

    Article  ADS  Google Scholar 

  20. Gressel, O., Nelson, R. P., Turner, N. J. & Ziegler, U. Global hydromagnetic simulations of a planet embedded in a dead zone: gap opening, gas accretion, and formation of a protoplanetary jet. Astrophys. J. 779, 59 (2013).

    Article  ADS  Google Scholar 

  21. Lyra, W., Johansen, A., Klahr, H. & Piskunov, N. Global magnetohydrodynamical models of turbulence in protoplanetary disks. I. A cylindrical potential on a Cartesian grid and transport of solids. Astron. Astrophys. 479, 883–901 (2008).

    Article  ADS  Google Scholar 

  22. Johansen, A., Youdin, A. & Klahr, H. Zonal flows and long-lived axisymmetric pressure bumps in magnetorotational turbulence. Astrophys. J. 697, 1269–1289 (2009).

    Article  ADS  Google Scholar 

  23. Suzuki, T. K. & Inutsuka, S.-i. Magnetohydrodynamic simulations of global accretion disks with vertical magnetic fields. Astrophys. J. 784, 121 (2014).

    Article  ADS  Google Scholar 

  24. Öberg, K. I., Murray-Clay, R. & Bergin, E. A. The effects of snowlines on C/O in planetary atmospheres. Astrophys. J. 743, L16 (2011).

    Article  ADS  Google Scholar 

  25. Madhusudhan, N. C/O ratio as a dimension for characterizing exoplanetary atmospheres. Astrophys. J. 758, 36 (2012).

    Article  ADS  Google Scholar 

  26. Devine, D. et al. A Lyα bright jet from a Herbig AE star. Astrophys. J. 542, L115–L118 (2000).

    Article  ADS  CAS  Google Scholar 

  27. Teague, R. & Foreman-Mackey, D. A robust method to measure centroids of spectral lines. Res. Not. Am. Astron. Soc. 2, 173 (2018).

    ADS  Google Scholar 

  28. Huang, J. et al. The Disk Substructures at High Angular Resolution Project (DSHARP). II. Characteristics of annular substructures. Astrophys. J. 869, L42 (2018).

    Article  ADS  Google Scholar 

  29. Teague, R. eddy. J. Open Source Softw. 4, 1220 (2019).

    Article  ADS  Google Scholar 

  30. Bailer-Jones, C. A. L., Rybizki, J., Fouesneau, M., Mantelet, G. & Andrae, R. Estimating distance from parallaxes. IV. Distances to 1.33 billion stars in Gaia data release 2. Astron. J. 156, 58 (2018).

    Article  ADS  Google Scholar 

  31. Teague, R. et al. Measuring turbulence in TW Hydrae with ALMA: methods and limitations. Astron. Astrophys. 592, A49 (2016).

    Article  Google Scholar 

  32. Benítez-Llambay, P. & Masset, F. S. FARGO3D: a new GPU-oriented MHD code. Astrophys. J. Suppl. Ser. 223, 11 (2016).

    Article  ADS  Google Scholar 

  33. Masset, F. FARGO: A fast eulerian transport algorithm for differentially rotating disks. Astron. Astrophys. Suppl. Ser. 141, 165–173 (2000).

    Article  ADS  Google Scholar 

  34. Liu, S.-F., Jin, S., Li, S., Isella, A. & Li, H. New constraints on turbulence and embedded planet mass in the HD 163296 disk from planet-disk hydrodynamic simulations. Astrophys. J. 857, 87 (2018).

    Article  ADS  Google Scholar 

  35. Balbus, S. A. & Hawley, J. F. Instability, turbulence, and enhanced transport in accretion disks. Rev. Mod. Phys. 70, 1–53 (1998).

    Article  ADS  Google Scholar 

Download references


This paper makes use of the following ALMA data: ADS/JAO.ALMA#2013.1.00366.S, ADS/JAO.ALMA#2013.1.00601.S and ADS/JAO.ALMA#2016.1.00484.L. ALMA is a partnership of the European Southern Observatory (ESO; representing its member states), the National Science Foundation (NSF; USA) and the National Institutes of Natural Sciences (Japan), together with the National Research Council (Canada), the National Science Council and the Academia Sinica Institute of Astronomy and Astrophysics (Taiwan), and the Korea Astronomy and Space Science Institute (Korea), in cooperation with Chile. The Joint ALMA Observatory is operated by ESO, Associated Universities, Inc./National Radio Astronomy Observatory (NRAO), and the National Astronomical Observatory of Japan. The NRAO is a facility of the NSF operated under cooperative agreement by Associated Universities, Inc. R.T and E.A.B. acknowledge funding from NSF grant AST-1514670 and NASA grant NNX16AB48G. J.B. acknowledges support from NASA grant NNX17AE31G, and computing resources provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center and by the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by NSF grant number ACI-1548562.

Author information

Authors and Affiliations



R.T. devised the method and analysed the data. J.B. ran the hydrodynamic simulations. All authors wrote the manuscript and were participants in the discussion and interpretation of results, determination of the conclusions and revision of the manuscript.

Corresponding author

Correspondence to Richard Teague.

Ethics declarations

Competing interests

The authors declare no competing interests.

Extended data figures and tables

Extended Data Fig. 1 A comparison of emission heights inferred for the 12CO emission.

The grey points in the background represent individual measurements following ref. 15, while the red contour shows the Gaussian process model of this surface including 1σ uncertainties, as described in ref. 6. Grey lines are random samples from the parametric fit derived from modelling the line-of-sight velocity map, with their spread demonstrating the 1σ uncertainties. The dust gap locations5,28 (D10 to D145) and radial location of the velocity perturbation found7 in 12CO, the ‘CO kink’, are marked. The major axis of the beam is shown for scale at bottom right.

Extended Data Fig. 2 Measured velocity structure of HD 163296.

Top row, projected rotation velocity vϕ,proj; second row, the residual from the 10th-order polynomial fit to vϕ to highlight the small-scale structure; third row, the vR values; and fourth row, the deviation in the shifted and aligned line centre from the systemic velocity. Left and right columns show results using the parametric and non-parametric emission surface, respectively. Velocities in the lower three rows have been corrected for projection effects assuming i = 47.6°. Blue error bars show the inferred velocities assuming both vR and vϕ components, while red error bars assume vR = 0 m s−1.

Extended Data Fig. 3 Measured velocity structure of the gas in the disk around HD 163296.

a, b, As Fig. 2 but using the non-parametric emission surface to deproject the data. Structure in the emission height outside 3″ is due to higher noise in the data, as described in the text.

Extended Data Fig. 4 Gas temperature and sound speed.

The figure shows the derived gas temperature (Tgas, top panel) and the derived gas sound speed (cs, bottom panel) as a function of radius. Error bars show the 1σ uncertainty. The drop in these values in the inner ~30 au (shaded area) is due to beam dilution.

Extended Data Fig. 5 Impact of the choice of velocity baseline.

The figure shows how the choice of vϕ,mod affects the residuals from vϕ, as in the second row of Extended Data Fig. 2. The top panel shows the different underlying models compared to the unprojected data, while the bottom panel shows the residual between the model and the observations. Regardless of the vϕ,mod chosen, the structure in δvϕ = (vϕ − vϕ,mod)/vϕ persists.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Teague, R., Bae, J. & Bergin, E.A. Meridional flows in the disk around a young star. Nature 574, 378–381 (2019).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing