한국   대만   중국   일본 
The comet-like composition of a protoplanetary disk as revealed by complex cyanides | Nature
Skip to main content

Thank you for visiting nature.com. 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:

The comet-like composition of a protoplanetary disk as revealed by complex cyanides

Nature volume ?520 ,? pages 198?201 ( 2015 ) Cite this article

Subjects

Abstract

Observations of comets and asteroids show that the solar nebula that spawned our planetary system was rich in water and organic molecules. Bombardment brought these organics to the young Earth’s surface 1 . Unlike asteroids, comets preserve a nearly pristine record of the solar nebula composition. The presence of cyanides in comets, including 0.01 per cent of methyl cyanide (CH 3 CN) with respect to water, is of special interest because of the importance of C?N bonds for abiotic amino acid synthesis 2 . Comet-like compositions of simple and complex volatiles are found in protostars, and can readily be explained by a combination of gas-phase chemistry (to form, for example, HCN) and an active ice-phase chemistry on grain surfaces that advances complexity 3 . Simple volatiles, including water and HCN, have been detected previously in solar nebula analogues, indicating that they survive disk formation or are re-formed in situ 4 , 5 , 6 , 7 . It has hitherto been unclear whether the same holds for more complex organic molecules outside the solar nebula, given that recent observations show a marked change in the chemistry at the boundary between nascent envelopes and young disks due to accretion shocks 8 . Here we report the detection of the complex cyanides CH 3 CN and HC 3 N (and HCN) in the protoplanetary disk around the young star MWC 480. We find that the abundance ratios of these nitrogen-bearing organics in the gas phase are similar to those in comets, which suggests an even higher relative abundance of complex cyanides in the disk ice. This implies that complex organics accompany simpler volatiles in protoplanetary disks, and that the rich organic chemistry of our solar nebula was not unique.

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

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

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

Figure 1: ALMA detections of simple and complex cyanides in the MWC 480 protoplanetary disk.
Figure 2: Spectra of detected cyanides in the MWC 480 protoplanetary disk.
Figure 3: Models of cyanide emission and radial distributions in the MWC 480 disk.

Similar content being viewed by others

References

  1. Hartogh, P. et al. Ocean-like water in the Jupiter-family comet 103P/Hartley 2. Nature 478 , 218?220 (2011)

    Article   ADS   CAS   Google Scholar  

  2. Goldman, N., Reed, E. J., Fried, L. E., William Kuo, I.-F. & Maiti, A. Synthesis of glycine-containing complexes in impacts of comets on early Earth. Nature Chem. 2 , 949?954 (2010)

    Article   ADS   CAS   Google Scholar  

  3. Herbst, E. & van Dishoeck, E. F. Complex organic interstellar molecules. Annu. Rev. Astron. Astrophys. 47 , 427?480 (2009)

    Article   ADS   CAS   Google Scholar  

  4. Dutrey, A., Guilloteau, S. & Guelin, M. Chemistry of protosolar-like nebulae: the molecular content of the DM Tau and GG Tau disks. Astron. Astrophys. 317 , L55?L58 (1997)

    ADS   CAS   Google Scholar  

  5. Carr, J. S. & Najita, J. R. Organic molecules and water in the planet formation region of young circumstellar disks. Science 319 , 1504?1506 (2008)

    Article   ADS   CAS   Google Scholar  

  6. Hogerheijde, M. R. et al. Detection of the water reservoir in a forming planetary system. Science 334 , 338?340 (2011)

    Article   ADS   CAS   Google Scholar  

  7. Cleeves, L. I. et al. The ancient heritage of water ice in the solar system. Science 345 , 1590?1593 (2014)

    Article   ADS   CAS   Google Scholar  

  8. Sakai, N. et al. Change in the chemical composition of infalling gas forming a disk around a protostar. Nature 507 , 78?80 (2014)

    Article   ADS   CAS   Google Scholar  

  9. Simon, M., Dutrey, A. & Guilloteau, S. Dynamical masses of T Tauri stars and calibration of pre-main-sequence evolution. Astrophys. J. 545 , 1034?1043 (2000)

    Article   ADS   CAS   Google Scholar  

  10. Guilloteau, S., Dutrey, A., Pietu, 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  

  11. Takami, M. et al. Surface geometry of protoplanetary disks inferred from near-infrared imaging polarimetry. Astrophys. J. 795 , 71 (2014)

    Article   ADS   Google Scholar  

  12. Chiang, E. I. & Goldreich, P. Spectral energy distributions of T Tauri stars with passive circumstellar disks. Astrophys. J. 490 , 368?376 (1997)

    Article   ADS   Google Scholar  

  13. D'Alessio, P., Calvet, N., Hartmann, L., Muzerolle, J. & Sitko, M. in Star Formation at High Angular Resolution (eds Burton, M. G., Jayawardhana, R. & Bourke, T. L.) 403?410 (IAU Symp. Vol. 221, 2004)

    Google Scholar  

  14. Dutrey, A. et al. Chemistry in disks. I. Deep search for N2H + in the protoplanetary disks around LkCa 15, MWC 480, and DM Tauri. Astron. Astrophys. 464 , 615?623 (2007)

    Article   ADS   CAS   Google Scholar  

  15. Oberg, K. I. et al. The disk imaging survey of chemistry with SMA. I. Taurus protoplanetary disk data. Astrophys. J. 720 , 480?493 (2010)

    Article   ADS   Google Scholar  

  16. Pontoppidan, K. M. et al. A Spitzer survey of mid-infrared molecular emission from protoplanetary disks. I. Detection rates. Astrophys. J. 720 , 887?903 (2010)

    Article   ADS   CAS   Google Scholar  

  17. Walsh, C., Millar, T. J. & Nomura, H. Chemical processes in protoplanetary disks. Astrophys. J. 722 , 1607?1623 (2010)

    Article   ADS   CAS   Google Scholar  

  18. Walsh, C. et al. Complex organic molecules in protoplanetary disks. Astron. Astrophys. 563 , A33 (2014)

    Article   Google Scholar  

  19. Mumma, M. J. & Charnley, S. B. The chemical composition of comets: emerging taxonomies and natal heritage. Annu. Rev. Astron. Astrophys. 49 , 471?524 (2011)

    Article   ADS   CAS   Google Scholar  

  20. Semenov, D. & Wiebe, D. Chemical evolution of turbulent protoplanetary disks and the solar nebula. Astrophys. J. Suppl. Ser. 196 , 25 (2011)

    Article   ADS   Google Scholar  

  21. van Dishoeck, E. F., Blake, G. A., Jansen, D. J. & Groesbeck, T. D. Molecular abundances and low-mass star formation. II. Organic and deuterated species toward IRAS 16293?2422. Astrophys. J. 447 , 760?782 (1995)

    Article   ADS   CAS   Google Scholar  

  22. Ciesla, F. J. & Sandford, S. A. Organic synthesis via irradiation and warming of ice grains in the solar nebula. Science 336 , 452?454 (2012)

    Article   ADS   CAS   Google Scholar  

  23. Favre, C., Cleeves, L. I., Bergin, E. A., Qi, C. & Blake, G. A. A significantly low CO abundance toward the TW Hya protoplanetary disk: a path to active carbon chemistry? Astrophys. J. 776 , L38 (2013)

    Article   ADS   Google Scholar  

  24. Tsiganis, K., Gomes, R., Morbidelli, A. & Levison, H. F. Origin of the orbital architecture of the giant planets of the Solar System. Nature 435 , 459?461 (2005)

    Article   ADS   CAS   Google Scholar  

  25. Walsh, K. J., Morbidelli, A., Raymond, S. N., O'Brien, D. P. & Mandell, A. M. A low mass for Mars from Jupiter’s early gas-driven migration. Nature 475 , 206?209 (2011)

    Article   ADS   CAS   Google Scholar  

  26. Pizzarello, S. Catalytic syntheses of amino acids and their significance for nebular and planetary chemistry. Meteorit. Planet. Sci. 47 , 1291?1296 (2012)

    Article   ADS   CAS   Google Scholar  

  27. O’Brien, D. P., Walsh, K. J., Morbidelli, A., Raymond, S. N. & Mandell, A. M. Water delivery and giant impacts in the Grand Tack scenario. Icarus 239 , 74?84 (2014)

    Article   ADS   Google Scholar  

  28. Oberg, K. I., Garrod, R. T., van Dishoeck, E. F. & Linnartz, H. Formation rates of complex organics in UV irradiated CH3OH-rich ices. I. Experiments. Astron. Astrophys. 504 , 891?913 (2009)

    Article   ADS   Google Scholar  

  29. Munoz Caro, G. M. et al. Amino acids from ultraviolet irradiation of interstellar ice analogues. Nature 416 , 403?406 (2002)

    Article   ADS   Google Scholar  

  30. Oberg, K. I. et al. Disk imaging survey of chemistry with SMA. II. Southern sky protoplanetary disk data and full sample statistics. Astrophys. J. 734 , 98 (2011)

    Article   ADS   Google Scholar  

  31. Lynden-Bell, D. & Pringle, J. E. The evolution of viscous discs and the origin of the nebular variables. Mon. Not. R. Astron. Soc. 168 , 603?637 (1974)

    Article   ADS   Google Scholar  

  32. Hartmann, L., Calvet, N., Gullbring, E. & D’Alessio, P. Accretion and the evolution of T Tauri disks. Astrophys. J. 495 , 385?400 (1998)

    Article   ADS   Google Scholar  

  33. Pietu, V., Dutrey, A., Guilloteau, S., Chapillon, E. & Pety, J. Resolving the inner dust disks surrounding LkCa 15 and MWC 480 at mm wavelengths. Astron. Astrophys. 460 , L43?L47 (2006)

    Article   ADS   Google Scholar  

  34. Dartois, E., Dutrey, A. & Guilloteau, S. Structure of the DM Tau outer disk: probing the vertical kinetic temperature gradient. Astron. Astrophys. 399 , 773?787 (2003)

    Article   ADS   Google Scholar  

  35. Rosenfeld, K. A., Andrews, S. M., Wilner, D. J., Kastner, J. H. & McClure, M. K. The structure of the evolved circumbinary disk around V4046 Sgr. Astrophys. J. 775 , 136 (2013)

    Article   ADS   Google Scholar  

  36. Qi, C. et al. Imaging of the CO snow line in a solar nebula analog. Science 341 , 630?632 (2013)

    Article   ADS   CAS   Google Scholar  

  37. Qi, C., Wilner, D. J., Aikawa, Y., Blake, G. A. & Hogerheijde, M. R. Resolving the chemistry in the disk of TW Hydrae. I. Deuterated species. Astrophys. J. 681 , 1396?1407 (2008)

    Article   ADS   CAS   Google Scholar  

  38. Qi, C. et al. Resolving the CO snow line in the disk around HD 163296. Astrophys. J. 740 , 84 (2011)

    Article   ADS   Google Scholar  

  39. Brinch, C. & Hogerheijde, M. R. LIME ? a flexible, non-LTE line excitation and radiation transfer method for millimeter and far-infrared wavelengths. Astron. Astrophys. 523 , A25 (2010)

    Article   ADS   Google Scholar  

  40. Wernli, M., Wiesenfeld, L., Faure, A. & Valiron, P. Rotational excitation of HC3N by H2 and He at low temperatures. Astron. Astrophys. 464 , 1147?1154 (2007)

    Article   ADS   CAS   Google Scholar  

  41. Dubernet, M., Nenadovic, L. & Doronin, N. in Astronomical Data Analysis Software and Systems XXI (eds Ballester, P., Egret, D. & Lorente, N. P. F.) 335?338 (Conf. Ser. Vol. 461, Astronomical Society of the Pacific, 2012)

    Google Scholar  

  42. Aikawa, Y. & Herbst, E. Molecular evolution in protoplanetary disks. Two-dimensional distributions and column densities of gaseous molecules. Astron. Astrophys. 351 , 233?246 (1999)

    ADS   CAS   Google Scholar  

  43. Walsh, C., Millar, T. J. & Nomura, H. Molecular line emission from a protoplanetary disk irradiated externally by a nearby massive star. Astrophys. J. 766 , L23 (2013)

    Article   ADS   Google Scholar  

  44. Aikawa, Y., Wakelam, V., Hersant, F., Garrod, R. T. & Herbst, E. From prestellar to protostellar cores. II. Time dependence and deuterium fractionation. Astrophys. J. 760 , 40 (2012)

    Article   ADS   Google Scholar  

  45. Wakelam, V. et al. A kinetic database for astrochemistry (KIDA). Astrophys. J. Suppl. Ser. 199 , 21 (2012)

    Article   ADS   Google Scholar  

  46. Cleeves, L. I., Bergin, E. A., Qi, C., Adams, F. C. & Oberg, K. I. Constraining the X-ray and cosmic ray ionization chemistry of the TW Hya protoplanetary disk: evidence for a sub-interstellar cosmic ray rate. Astrophys. J. 799 , 204 (2015)

    Article   ADS   Google Scholar  

  47. Furuya, K. & Aikawa, Y. Reprocessing of ices in turbulent protoplanetary disks: carbon and nitrogen chemistry. Astrophys. J. 790 , 97 (2014)

    Article   ADS   Google Scholar  

  48. Yamamoto, T., Nakagawa, N. & Fukui, Y. The chemical composition and thermal history of the ice of a cometary nucleus. Astron. Astrophys. 122 , 171?176 (1983)

    ADS   CAS   Google Scholar  

  49. Garrod, R. T. & Herbst, E. Formation of methyl formate and other organic species in the warm-up phase of hot molecular cores. Astron. Astrophys. 457 , 927?936 (2006)

    Article   ADS   CAS   Google Scholar  

  50. Collings, M. P. et al. A laboratory survey of the thermal desorption of astrophysically relevant molecules. Mon. Not. R. Astron. Soc. 354 , 1133?1140 (2004)

    Article   ADS   Google Scholar  

  51. van Dishoeck, E. F., Jonkheid, B. & van Hemert, M. C. Photoprocesses in protoplanetary disks. Faraday Discuss. 133 , 231?243 (2006)

    Article   ADS   CAS   Google Scholar  

  52. Walsh, C., Nomura, H., Millar, T. J. & Aikawa, Y. Chemical processes in protoplanetary disks. II. On the importance of photochemistry and X-ray ionization. Astrophys. J. 747 , 114 (2012)

    Article   ADS   Google Scholar  

  53. Nomura, H., Aikawa, Y., Tsujimoto, M., Nakagawa, Y. & Millar, T. J. Molecular hydrogen emission from protoplanetary disks. II. Effects of X-ray irradiation and dust evolution. Astrophys. J. 661 , 334?353 (2007)

    Article   ADS   CAS   Google Scholar  

  54. Fayolle, E. C., Oberg, K. I., Cuppen, H. M., Visser, R. & Linnartz, H. Laboratory H2O:CO2 ice desorption data: entrapment dependencies and its parameterization with an extended three-phase model. Astron. Astrophys. 529 , A74 (2011)

    Article   ADS   Google Scholar  

  55. Gratier, P. et al. The IRAM-30 m line survey of the Horsehead PDR. III. High abundance of complex (iso-)nitrile molecules in UV-illuminated gas. Astron. Astrophys. 557 , A101 (2013)

    Article   Google Scholar  

  56. Bergin, E., Calvet, N., D'Alessio, P. & Herczeg, G. J. The effects of UV continuum and Ly α radiation on the chemical equilibrium of T Tauri disks. Astrophys. J. 591 , L159?L162 (2003)

    Article   ADS   CAS   Google Scholar  

  57. Graninger, D. M., Herbst, E., Oberg, K. I. & Vasyunin, A. I. The HNC/HCN ratio in star-forming regions. Astrophys. J. 787 , 74 (2014)

    Article   ADS   Google Scholar  

Download references

Acknowledgements

We acknowledge comments from E. van Dishoeck. This Letter makes use of ALMA data. 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. The National Radio Astronomy Observatory is a facility of the NSF operated under cooperative agreement by Associated Universities, Inc. K.I.O. acknowledges A. Leroy and the NAASC for assistance with calibration and imaging, and also acknowledges funding from the Simons Collaboration on the Origins of Life (SCOL), the Alfred P. Sloan Foundation, and the David and Lucile Packard Foundation. D.J.W. acknowledges funding from NASA Origins of Solar Systems (grant no. NNX11AK63).

Author information

Authors and Affiliations

  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA,

    Karin I. Oberg,?Viviana V. Guzman,?Chunhua Qi,?Sean M. Andrews,?Ryan Loomis?&?David J. Wilner

  2. Leiden Observatory, Leiden University, PO Box 9513, 2300 CA Leiden, The Netherlands,

    Kenji Furuya

  3. Kobe University, 1-1 Rokkodaicho, Nada Ward, Kobe, Hyogo Prefecture 657-0013, Japan,

    Yuri Aikawa

Authors
  1. Karin I. Oberg
    View author publications

    You can also search for this author in PubMed  Google Scholar

  2. Viviana V. Guzman
    View author publications

    You can also search for this author in PubMed  Google Scholar

  3. Kenji Furuya
    View author publications

    You can also search for this author in PubMed  Google Scholar

  4. Chunhua Qi
    View author publications

    You can also search for this author in PubMed  Google Scholar

  5. Yuri Aikawa
    View author publications

    You can also search for this author in PubMed  Google Scholar

  6. Sean M. Andrews
    View author publications

    You can also search for this author in PubMed  Google Scholar

  7. Ryan Loomis
    View author publications

    You can also search for this author in PubMed  Google Scholar

  8. David J. Wilner
    View author publications

    You can also search for this author in PubMed  Google Scholar

Contributions

K.I.O. led the overall project, reduced the data, assisted by V.V.G. and R.L., and wrote the manuscript with revisions from S.M.A. and D.J.W. V.V.G., assisted by C.Q., performed the parametric modelling and abundance extraction. K.F. performed the astrochemical modelling, and interpreted the results with Y.A. All authors contributed to discussions of the results and commented on the manuscript.

Corresponding author

Correspondence to Karin I. Oberg .

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Additional information

The ALMA program number for the presented data is 2013.1.00226.

Extended data figures and tables

Extended Data Figure 1 Model of the physical structure of the MWC 480 protoplanetary disk.

a , Radial (distance R ) and vertical (distance Z ) disk temperature profile (colour: see colour scale on right, contours: the gas temperature T kin = 20, 30, 50, 100 and 1,000 K). b , Radial (R) and vertical (Z) density profile (colour: see colour scale on the right, contours: hydrogen density n H 10 10 , 10 8 , 10 6 and 10 4 cm ?3 ). Z / R = 0.2 is marked with a dashed line.

Extended Data Figure 2 Synthetic observations of H 13 CN, HC 3 N and CH 3 CN for different density

slopes α . The models are based on best fit to data for different choices of α , with the ranges chosen based on the emission pattern for each molecule. Left column, H 13 CN; middle column, HC 3 N; right column, CH 3 CN. Top row, α = 0; middle row, α = 1; bottom row, α = 2. a ? g , Integrated emission maps (colour: see colour scale on the right). Black contours are the observed [3, 4, 5, 7, 10] σ in Fig. 1 . The synthesized beam is shown in the bottom left corner of each panel. Note the change in emission profile between α = 1 and 2 for HC 3 N.

Extended Data Figure 3 Models of gaseous CH 3 CN/HCN abundance ratios under different physical conditions.

a ? l , The CH 3 CN/HCN abundance ratio on a logarithmic scale (colour: see colour scale on the bottom and numbers on contours). The ultraviolet radiation flux increases from left to right from G 0 = 1 ( a , d , g , j ) to G 0 = 10 ( b , e , h , k ) to G 0 = 100 ( c , f , i , l ), where G 0 is the scaling factor in multiples of the local interstellar radiation field. The ionization rate of H 2 increases from top to bottom from 10 ?17 s ?1 ( a ? c ) to 10 ?16 s ?1 ( d ? f ) to 10 ?15 s ?1 ( g ? i ) to 10 ?14 s ?1 ( j ? l ).

Extended Data Figure 4 Models of gaseous CH 3 CN in disks with and without turbulent diffusion.

a , The abundance of CH 3 CN with respect to the hydrogen density n H (colour: see colour scale on the right) as a function of disk radius ( R ) and height scaled by the radius ( Z / R ) in a model without turbulence. The dashed lines indicate gas temperatures of [30, 50, 100] K. b , c , As a but in disk models that include turbulence parameterized by α z = 10 ?3 ( b ) and α z = 10 ?2 ( c ). d , The vertically integrated column density of CH 3 CN from a ? c (solid line: α z = 0, dashed line: α z = 10 ?3 , dotted line: α z = 10 ?2 ).

Extended Data Figure 5 Models of gaseous CH 3 CN/HCN ratios in disks with and without turbulent diffusion.

a ? d , As in Extended Data Fig. 4 but for CH 3 CN/HCN ratio.

Extended Data Figure 6 Models of gas-to-ice ratios of HCN in disks with and without turbulent diffusion.

a ? d , As in Extended Data Fig. 4 but for ice-to-gas ratios of HCN.

Extended Data Figure 7 Models of gas-to-ice ratios of CH 3 CN in disks with and without turbulent diffusion.

a ? d , As in Extended Data Fig. 4 but for ice-to-gas ratios of CH 3 CN.

Extended Data Table 1 Physical model for the disk of MWC 480
Full size table

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Cite this article

Oberg, K., Guzman, V., Furuya, K. et al. The comet-like composition of a protoplanetary disk as revealed by complex cyanides. Nature 520 , 198?201 (2015). https://doi.org/10.1038/nature14276

Download citation

  • Received :

  • Accepted :

  • Issue Date :

  • DOI : https://doi.org/10.1038/nature14276

This article is cited by

Comments

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.

Search

Advanced search

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