Possible planet formation in the young, low-mass, multiple stellar system GG Tau A



The formation of planets around binary stars may be more difficult than around single stars1,2,3. In a close binary star (with a separation of less than a hundred astronomical units), theory predicts the presence of circumstellar disks around each star, and an outer circumbinary disk surrounding a gravitationally cleared inner cavity around the stars4,5. Given that the inner disks are depleted by accretion onto the stars on timescales of a few thousand years, any replenishing material must be transferred from the outer reservoir to fuel planet formation (which occurs on timescales of about one million years). Gas flowing through disk cavities has been detected in single star systems6. A circumbinary disk was discovered around the young low-mass binary system GG Tau A (ref. 7), which has recently been shown to be a hierarchical triple system8. It has one large inner disk9 around the single star, GG Tau Aa, and shows small amounts of shocked hydrogen gas residing within the central cavity10, but other than a single weak detection11, the distribution of cold gas in this cavity or in any other binary or multiple star system has not hitherto been determined. Here we report imaging of gas fragments emitting radiation characteristic of carbon monoxide within the GG Tau A cavity. From the kinematics we conclude that the flow appears capable of sustaining the inner disk (around GG Tau Aa) beyond the accretion lifetime, leaving time for planet formation to occur there. These results show the complexity of planet formation around multiple stars and confirm the general picture predicted by numerical simulations.

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Figure 1: ALMA and IRAM images of GG Tau A.


  1. 1

    Nelson, A. F. Planet formation is unlikely in equal-mass binary systems with A 50 AU. Astrophys. J. 537, L65–L68 (2000)

    CAS  Article  ADS  Google Scholar 

  2. 2

    Mayer, L., Wadsley, J., Quinn, T. & Stadel, J. Gravitational instability in binary protoplanetary discs: new constraints on giant planet formation. Mon. Not. R. Astron. Soc. 363, 641–648 (2005)

    Article  ADS  Google Scholar 

  3. 3

    Thébault, P., Marzari, F. & Scholl, H. Relative velocities among accreting planetesimals in binary systems: the circumprimary case. Icarus 183, 193–206 (2006)

    Article  ADS  Google Scholar 

  4. 4

    Artymowicz, P. & Lubow, S. H. Dynamics of binary-disk interaction. 1: Resonances and disk gap sizes. Astrophys. J. 421, 651–667 (1994)

    Article  ADS  Google Scholar 

  5. 5

    Bate, M. R. & Bonnell, I. A. Accretion during binary star formation — II. Gaseous accretion and disc formation. Mon. Not. R. Astron. Soc. 285, 33–48 (1997)

    Article  ADS  Google Scholar 

  6. 6

    Casassus, S. et al. Flows of gas through a protoplanetary gap. Nature 493, 191–194 (2013)

    CAS  Article  ADS  Google Scholar 

  7. 7

    Skrutskie, M. F. et al. Detection of circumstellar gas associated with GG Tauri. Astrophys. J. 409, 422–428 (1993)

    CAS  Article  ADS  Google Scholar 

  8. 8

    Di Folco, E. et al. GG Tauri: the fifth element. Astron. Astrophys. 565, L2 (2014)

    Article  ADS  Google Scholar 

  9. 9

    Andrews, S. M. et al. Resolved multifrequency radio observations of GG Tau. Astrophys. J. 787, 148 (2014)

    Article  ADS  Google Scholar 

  10. 10

    Beck, T. L. et al. Circumbinary gas accretion onto a central binary: infrared molecular hydrogen emission from GG Tau A. Astrophys. J. 754, 72 (2012)

    Article  ADS  CAS  Google Scholar 

  11. 11

    Guilloteau, S. & Dutrey, A. G. G. in The Formation of Binary Stars (eds Zinnecker, H. & Mathieu, R. ) 229–233 (IAU Symposium, Vol. 200, 2001)

    Google Scholar 

  12. 12

    Hartigan, P. & Kenyon, S. J. A spectroscopic survey of subarcsecond binaries in the Taurus-Auriga dark cloud with the Hubble Space Telescope. Astrophys. J. 583, 334–357 (2003)

    CAS  Article  ADS  Google Scholar 

  13. 13

    White, R. J., Ghez, A. M., Reid, I. N. & Schultz, G. A test of pre-main-sequence evolutionary models across the stellar/substellar boundary based on spectra of the young quadruple GG Tauri. Astrophys. J. 520, 811–821 (1999)

    CAS  Article  ADS  Google Scholar 

  14. 14

    Dutrey, A., Guilloteau, S. & Simon, M. Images of the GG Tauri rotating ring. Astron. Astrophys. 286, 149–159 (1994)

    CAS  ADS  Google Scholar 

  15. 15

    Piétu, V., Gueth, F., Hily-Blant, P., Schuster, K.-F. & Pety, J. High resolution imaging of the GG Tauri system at 267 GHz. Astron. Astrophys. 528, A81 (2011)

    Article  ADS  Google Scholar 

  16. 16

    Skemer, A. J. et al. Dust grain evolution in spatially resolved T Tauri binaries. Astrophys. J. 740, 43 (2011)

    Article  ADS  CAS  Google Scholar 

  17. 17

    Artymowicz, P., Clarke, C. J., Lubow, S. H. & Pringle, J. E. The effect of an external disk on the orbital elements of a central binary. Astrophys. J. 370, L35–L38 (1991)

    Article  ADS  Google Scholar 

  18. 18

    Beust, H. & Dutrey, A. Dynamics of the young multiple system GG Tauri. I. Orbital fits and inner edge of the circumbinary disk of GG Tau A. Astron. Astrophys. 439, 585–594 (2005)

    Article  ADS  Google Scholar 

  19. 19

    Pierens, A. & Nelson, R. P. On the migration of protoplanets embedded in circumbinary disks. Astron. Astrophys. 472, 993–1001 (2007)

    Article  ADS  MATH  Google Scholar 

  20. 20

    Pierens, A. & Nelson, R. P. Migration and gas accretion scenarios for the Kepler 16, 34, and 35 circumbinary planets. Astron. Astrophys. 556, A134 (2013)

    Article  ADS  Google Scholar 

  21. 21

    Guilloteau, S., Dutrey, A. & Simon, M. G. G. Tauri: the ring world. Astron. Astrophys. 348, 570–578 (1999)

    CAS  ADS  Google Scholar 

  22. 22

    Dutrey, A. et al. Physical and chemical structure of planet-forming disks probed by millimeter observations and modeling. Preprint at http://arXiv.org/abs/1402.3503 (2014)

  23. 23

    Delorme, P. et al. Direct-imaging discovery of a 12–14 Jupiter-mass object orbiting a young binary system of very low-mass stars. Astron. Astrophys. 553, L5 (2013)

    Article  ADS  Google Scholar 

  24. 24

    Duchêne, G. & Kraus, A. Stellar multiplicity. Annu. Rev. Astron. Astrophys. 51, 269–310 (2013)

    Article  ADS  CAS  Google Scholar 

  25. 25

    Moriarty-Schieven, G. H. & Butner, H. M. A submillimeter-wave “flare” from GG Tauri? Astrophys. J. 474, 768–773 (1997)

    Article  ADS  Google Scholar 

  26. 26

    Thi, W.-F., van Dishoeck, E. F., Blake, G. A., van Zadelhoff, G.-J. & Hogerheijde, M. R. Detection of H2 pure rotational line emission from the GG Tauri binary system. Astrophys. J. 521, L63–L66 (1999)

    CAS  Article  ADS  Google Scholar 

  27. 27

    Pety, J., Gueth, F. & Guilloteau, S. ALMA+ACA simulation tool. ALMA Memo 386, 1–10 (2002)

    Google Scholar 

  28. 28

    Ducourant, C. et al. Pre-main sequence star proper motion catalogue. Astron. Astrophys. 438, 769–778 (2005)

    Article  ADS  Google Scholar 

  29. 29

    Piétu, V., Guilloteau, S., Di Folco, E., Dutrey, A. & Boehler, Y. Faint disks around classical T Tauri stars: small but dense enough to form planets. Astron. Astrophys. 564, A95 (2014)

    Article  ADS  CAS  Google Scholar 

  30. 30

    van der Tak, F. F. S., Black, J. H., Schöier, F. L., Jansen, D. J. & van Dishoeck, E. F. A computer program for fast non-LTE analysis of interstellar line spectra. With diagnostic plots to interpret observed line intensity ratios. Astron. Astrophys. 468, 627–635 (2007)

    Article  ADS  Google Scholar 

  31. 31

    Nguyen, D. C., Brandeker, A., van Kerkwijk, M. H. & Jayawardhana, R. Close companions to young stars. I. A large spectroscopic survey in Chamaeleon I and Taurus-Auriga. Astrophys. J. 745, 119 (2012)

    Article  ADS  CAS  Google Scholar 

  32. 32

    Guilloteau, S. & Dutrey, A. Physical parameters of the Keplerian protoplanetary disk of DM Tauri. Astron. Astrophys. 339, 467–476 (1998)

    ADS  Google Scholar 

  33. 33

    Rosenfeld, K. A., Chiang, E. & Andrews, S. M. Fast radial flows in transition disk holes. Astrophys. J. 782, 62 (2014)

    Article  ADS  Google Scholar 

  34. 34

    Guilloteau, S. et al. Chemistry in disks. VIII. The CS molecule as an analytic tracer of turbulence in disks. Astron. Astrophys. 548, A70 (2012)

    Article  CAS  Google Scholar 

  35. 35

    Beckwith, S. V. W. & Sargent, A. I. Molecular line emission from circumstellar disks. Astrophys. J. 402, 280–291 (1993)

    CAS  Article  ADS  Google Scholar 

  36. 36

    Boehler, Y., Dutrey, A., Guilloteau, S. & Piétu, V. Probing dust settling in proto-planetary discs with ALMA. Mon. Not. R. Astron. Soc. 431, 1573–1586 (2013)

    Article  ADS  Google Scholar 

  37. 37

    Piétu, V., Dutrey, A. & Guilloteau, S. Probing the structure of protoplanetary disks: a comparative study of DM Tau, LkCa 15, and MWC 480. Astron. Astrophys. 467, 163–178 (2007)

    Article  ADS  CAS  Google Scholar 

  38. 38

    Guilloteau, S., Dutrey, A., Piétu, V. & Boehler, Y. A dual-frequency sub-arcsecond study of proto-planetary disks at mm wavelengths: first evidence for radial variations of the dust properties. Astron. Astrophys. 529, A105 (2011)

    Article  ADS  Google Scholar 

  39. 39

    Madlener, D., Wolf, S., Dutrey, A. & Guilloteau, S. The circumstellar disk of HH 30. Searching for signs of disk evolution with multi-wavelength modeling. Astron. Astrophys. 543, A81 (2012)

    Article  ADS  Google Scholar 

  40. 40

    de Gregorio-Monsalvo, I. et al. Unveiling the gas-and-dust disk structure in HD 163296 using ALMA observations. Astron. Astrophys. 557, A133 (2013)

    Article  CAS  Google Scholar 

  41. 41

    van der Marel, N. et al. A major asymmetric dust trap in a transition disk. Science 340, 1199–1202 (2013)

    CAS  Article  ADS  Google Scholar 

  42. 42

    Beust, H. & Dutrey, A. Dynamics of the young multiple system GG Tauri. II. Relation between the stellar system and the circumbinary disk. Astron. Astrophys. 446, 137–154 (2006)

    Article  ADS  Google Scholar 

  43. 43

    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 

  44. 44

    Wolf, S., Gueth, F., Henning, T. & Kley, W. Detecting planets in protoplanetary disks: a prospective study. Astrophys. J. 566, L97–L99 (2002)

    Article  ADS  Google Scholar 

  45. 45

    Wolf, S. & D’Angelo, G. On the observability of giant protoplanets in circumstellar disks. Astrophys. J. 619, 1114–1122 (2005)

    Article  ADS  Google Scholar 

  46. 46

    Boley, A. C. et al. Constraining the planetary system of Fomalhaut using high-resolution ALMA observations. Astrophys. J. 750, L21 (2012)

    Article  ADS  Google Scholar 

  47. 47

    Crida, A., Morbidelli, A. & Masset, F. On the width and shape of gaps in protoplanetary disks. Icarus 181, 587–604 (2006)

    Article  ADS  Google Scholar 

  48. 48

    Takeuchi, T., Miyama, S. M. & Lin, D. N. C. Gap formation in protoplanetary disks. Astrophys. J. 460, 832–847 (1996)

    Article  ADS  Google Scholar 

  49. 49

    Dutrey, A. et al. Cavities in inner disks: the GM Aurigae case. Astron. Astrophys. 490, L15–L18 (2008)

    CAS  Article  ADS  Google Scholar 

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ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada) and NSC and ASIAA (Taiwan), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). A.D. thanks the French programmes PNP, PCMI, PNPS and ASA for providing funding for this study.

Author information




A.D. led the project and participated in data reduction. All authors contributed to the data analysis, discussed the results and commented on the manuscript.

Corresponding author

Correspondence to Anne Dutrey.

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The authors declare no competing financial interests.

Additional information

This paper makes use of the following ALMA data: ADS/JAO.ALMA2011.0.00059.

Extended data figures and tables

Extended Data Figure 1 ALMA CO J = 6–5 velocity channel map.

For each spectroscopic channel, the velocity is given at top left. a, Full map; b, inner zoom. The beam size is 0.29″ × 0.25″ at PA 68°. The level step is 100 mJy per beam or 3.51 K corresponding to 3.4σ.

Extended Data Figure 2 IRAM CO J = 2–1 velocity channel map.

For each spectroscopic channel, the velocity is given at top left. a, Full map; b, inner zoom. The beam size is 0.68″ × 0.31″ at PA 21°. The level step is 50 mJy per beam or 5.48 K corresponding to 3.85σ.

Extended Data Figure 3 Montage of the CO J = 6–5 data.

False colours and black contours show the integrated area. The velocity gradient is given in thick contours: blue (gas approaching), black (systemic velocity) and red (gas receding). Stars show the location of Aa (south) and Ab (north). The two large ellipses show the ring edges. The three spectra sets (y axis, intensity in units of Jy per beam; x axis, velocity in units of km s−1) show the velocity gradient along the northern/southern CO J = 6–5 clump, respectively (dominated by rotation). On spectra, the red line is the systemic velocity (6.4 km s−1). From east to west, the black contours correspond to velocity contours of 6.0, 6.4 and 6.8 km s−1. The systemic velocity contour passes between the two stars (barycentre). The single spectrum corresponds to the location of the hotspot.

Extended Data Figure 4 Dust ring best model.

a, ALMA continuum data at 0.45 mm (emission from Aa circumstellar disk has been removed). b, Best model at 0.45 mm, same contour levels. c, Difference between the observations and the best model, contour levels correspond to 2σ. d, e, f, As a, b, c but for the IRAM continuum data at 1.3 mm.

Extended Data Table 1 Parameters relevant to the analysis of the ALMA data
Extended Data Table 2 Best fit results for the GG Tau circumbinary dust disk, as derived from the whole continuum data set

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Dutrey, A., Di Folco, E., Guilloteau, S. et al. Possible planet formation in the young, low-mass, multiple stellar system GG Tau A. Nature 514, 600–602 (2014). https://doi.org/10.1038/nature13822

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