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:

A giant impact as the likely origin of different twins in the Kepler-107 exoplanet system

Nature Astronomy volume 3, pages 416–423 (2019)Cite this article

Subjects

Abstract

Measures of exoplanet bulk densities indicate that small exoplanets with radius less than 3 Earth radii (R⊕) range from low-density sub-Neptunes containing volatile elements1 to higher-density rocky planets with Earth-like2 or iron-rich3 (Mercury-like) compositions. Such astonishing diversity in observed small exoplanet compositions may be the product of different initial conditions of the planet-formation process or different evolutionary paths that altered the planetary properties after formation4. Planet evolution may be especially affected by either photoevaporative mass loss induced by high stellar X-ray and extreme ultraviolet (XUV) flux5 or giant impacts6. Although there is some evidence for the former7,8, there are no unambiguous findings so far about the occurrence of giant impacts in an exoplanet system. Here, we characterize the two innermost planets of the compact and near-resonant system Kepler-107 (ref. 9). We show that they have nearly identical radii (about 1.5–1.6R⊕), but the outer planet Kepler-107 c is more than twice as dense (about 12.6 g cm–3) as the innermost Kepler-107 b (about 5.3 g cm−3). In consequence, Kepler-107 c must have a larger iron core fraction than Kepler-107 b. This imbalance cannot be explained by the stellar XUV irradiation, which would conversely make the more-irradiated and less-massive planet Kepler-107 b denser than Kepler-107 c. Instead, the dissimilar densities are consistent with a giant impact event on Kepler-107 c that would have stripped off part of its silicate mantle. This hypothesis is supported by theoretical predictions from collisional mantle stripping10, which match the mass and radius of Kepler-107 c.

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

Fig. 1: Radial velocity measurements of Kepler-107 with HARPS-N.
Fig. 2: Mass–radius diagram of exoplanets smaller than 3R⊕.
Fig. 3: Smoothed particle hydrodynamical collision simulation.

Similar content being viewed by others

Data availability

The RV data that support the findings of this study and have been used to produce some of the plots are available in the Supplementary Information. Kepler data are available at the Mikulski Archive for Space Telescopes (https://archive.stsci.edu/kepler/).

References

  1. Lissauer, J. J. et al. All six planets known to orbit Kepler-11 have low densities. Astrophys. J. 770, 131 (2013).

    Article  ADS  Google Scholar 

  2. Dressing, C. D. et al. The mass of Kepler-93b and the composition of terrestrial planets. Astrophys. J. 800, 135 (2015).

    Article  ADS  Google Scholar 

  3. Santerne, A. et al. An Earth-sized planet with a Mercury-like composition. Nat. Astron. 2, 393–400 (2018).

    Article  ADS  Google Scholar 

  4. Schlichting, H. E. in Handbook of Exoplanets (eds Deeg, H. & Belmonte, J.) 2345–2364 (Springer, Cham, 2018).

  5. Lopez, E. D., Fortney, J. J. & Miller, N. How thermal evolution and mass-loss sculpt populations of super-Earths and sub-Neptunes: application to the Kepler-11 system and beyond. Astrophys. J. 761, 59 (2012).

    Article  ADS  Google Scholar 

  6. Liu, S.-F., Hori, S., Lin, D. N. C. & Asphaug, E. Giant impact: an efficient mechanism for devolatilization of super-Earths. Astrophys. J. 812, 164 (2015).

    Article  ADS  Google Scholar 

  7. Lopez, E. & Fortney, J. J. Understanding the mass-radius relation for sub-Neptunes: radius as a proxy for composition. Astrophys. J. 792, 17 (2014).

    Article  ADS  Google Scholar 

  8. Lundkvist, M. S. et al. Hot super-Earths stripped by their host stars. Nat. Commun. 7, 11201 (2016).

    Article  ADS  Google Scholar 

  9. Rowe, J. F. et al. Validation of Kepler’s multiple planet candidates. III. Light curve analysis and announcement of hundreds of new multi-planet systems. Astrophys. J. 784, 45 (2014).

    Article  ADS  Google Scholar 

  10. Marcus, R. A., Sasselov, D., Hernquist, L. & Stewart, S. T. Minimum radii of super-Earths: constraints from giant impacts. Astrophys. J. Lett. 712, L73–L76 (2010).

    Article  ADS  Google Scholar 

  11. Terquem, C. & Papaloizou, J. C. B. Migration and the formation of systems of hot super-Earths and Neptunes. Astrophys. J. 654, 1110–1120 (2007).

    Article  ADS  Google Scholar 

  12. Van Eylen, V. & Albrecht, S. Eccentricity from transit photometry: small planets in Kepler multi-planet systems have low eccentricities. Astrophys. J. 808, 126 (2015).

    Article  ADS  Google Scholar 

  13. Holczer, T. et al. Transit timing observations from Kepler. IX. Catalog of the full long-cadence data set. Astrophys. J. Suppl. Ser. 225, 9 (2016).

    Article  ADS  Google Scholar 

  14. Cosentino, R. et al. HARPS-N: the new planet hunter at TNG. Proc. SPIE 8446, 84461V (2012).

    Google Scholar 

  15. Buchhave, L. A. et al. An abundance of small planets around stars with a wide range of metallicities. Nature 486, 375–377 (2012).

    Article  ADS  Google Scholar 

  16. Silva Aguirre, V. et al. Ages and fundamental properties of Kepler exoplanet host stars from asteroseismology. Mon. Not. R. Astron. Soc. 452, 2127–2148 (2015).

    Article  ADS  Google Scholar 

  17. Huber, D. et al. Fundamental properties of Kepler planet-candidate host stars using asteroseismology. Astrophys. J. 767, 127 (2013).

    Article  ADS  Google Scholar 

  18. Bonomo, A. S. et al. Characterization of the planetary system Kepler-101 with HARPS-N. A hot super-Neptune with an Earth-sized low-mass companion. Astron. Astrophys. 572, A2 (2014).

    Article  Google Scholar 

  19. Damasso, M. et al. Eyes on K2-3: a system of three likely sub-Neptunes characterized with HARPS-N and HARPS. Astron. Astrophys. 615, A69 (2018).

    Article  Google Scholar 

  20. Zeng, L. & Sasselov, D. A detailed model grid for solid planets from 0.1 to 100 Earth masses. Publ. Astron. Soc. Pac. 125, 227 (2013).

    Article  ADS  Google Scholar 

  21. Lopez, E. & Fortney, J. J. The role of core mass in controlling evaporation: the Kepler radius distribution and the Kepler-36 density dichotomy. Astrophys. J. 776, 2 (2013).

    Article  ADS  Google Scholar 

  22. Leinhardt, Z. M. & Stewart, S. T. Collisions between gravity-dominated bodies. I. Outcome regimes and scaling laws. Astrophys. J. 745, 79 (2012).

    Article  ADS  Google Scholar 

  23. Marcus, R. A., Stewart, S. T., Sasselov, D. & Hernquist, L.Collisional stripping and disruption of super-Earths. Astrophys. J. Lett. 700, L118–L122 (2009).

    Article  ADS  Google Scholar 

  24. Chau, A., Reinhardt, C., Helled, R. & Stadel, J. Forming Mercury by giant impacts. Astrophys. J. 865, 35 (2018).

    Article  ADS  Google Scholar 

  25. Guenther, E. W. et al. K2-106, a system containing a metal-rich planet and a planet of lower density. Astron. Astrophys. 608, A93 (2017).

    Article  Google Scholar 

  26. Ebel, D. S. & Stewart, S. T. in Mercury: The View After MESSENGER (eds Solomon, S. C., Nittler, L. R. & Anderson, B. J.) 497–515 (Cambridge Univ. Press, Cambridge, 2018).

  27. Benz, W., Anic, A., Horner, J. & Whitby, J. A. in Mercury (eds Balogh, A. et al.) Space Sciences Series of ISSI Vol. 26, 7–20 (Springer, New York, 2008).

  28. Lock, S. J. et al. The origin of the Moon within a terrestrial synestia. J. Geophys. Res. 123, 910–951 (2018).

    Article  Google Scholar 

  29. Safronov, V. S. Sizes of the largest bodies falling onto the planets during their formation. Sov. Astron. 9, 987–991 (1966).

    ADS  Google Scholar 

  30. Berger, T. A. et al. Revised radii of Kepler stars and planets using Gaia Data Release 2. Astrophys. J. 866, 99 (2018).

    Article  ADS  Google Scholar 

  31. Jenkins, J. M. et al. Overview of the Kepler Science Processing Pipeline. Astrophys. J. Lett. 713, L87–L91 (2010).

    Article  ADS  Google Scholar 

  32. Bonomo, A. S. et al. Detection of Neptune-size planetary candidates with CoRoT data. Comparison with the planet occurrence rate derived from Kepler. Astron. Astrophys. 547, A110 (2012).

    Article  Google Scholar 

  33. Handberg, R. & Lund, M. N. Automated preparation of Kepler time series of planet hosts for asteroseismic analysis. Mon. Not. R. Astron. Soc. 445, 2698–2709 (2014).

    Article  ADS  Google Scholar 

  34. García, R. A. et al. Preparation of Kepler light curves for asteroseismic analyses. Mon. Not. R. Astron. Soc. 414, L6–L10 (2011).

    Article  ADS  Google Scholar 

  35. Kjeldsen, H. & Frandsen, S. High-precision time-resolved CCD photometry. Publ. Astron. Soc. Pacif. 104, 413–434 (1992).

    Article  ADS  Google Scholar 

  36. Handberg, R. & Campante, T. L. Bayesian peak-bagging of solar-like oscillators using MCMC: a comprehensive guide. Astron. Astrophys. 527, A56 (2011).

    Article  ADS  Google Scholar 

  37. Lund, M. N. et al. Standing on the shoulders of dwarfs: the Kepler Asteroseismic LEGACY Sample. I. Oscillation mode parameters. Astrophys. J. 835, 172 (2017).

    Article  ADS  Google Scholar 

  38. Corsaro, E. & De Ridder, J. DIAMONDS: a new Bayesian nested sampling tool. Application to peak bagging of solar-like oscillations. Astron. Astrophys. 571, A71 (2014).

    Article  Google Scholar 

  39. White, T. R. et al. Asteroseismic diagrams from a survey of solar-like oscillations with Kepler. Astrophys. J. Lett. 742, L3 (2011).

    Article  ADS  Google Scholar 

  40. Davies, G. R. et al. Oscillation frequencies for 35 Kepler solar-type planet-hosting stars using Bayesian techniques and machine learning. Mon. Not. R. Astron. Soc. 456, 2183–2195 (2016).

    Article  ADS  Google Scholar 

  41. Mortier, A. et al. Correcting the spectroscopic surface gravity using transits and asteroseismology. No significant effect on temperatures or metallicities with ARES and MOOG in local thermodynamic equilibrium. Astron. Astrophys. 572, A95 (2014).

    Article  Google Scholar 

  42. Mortier, A. et al. New and updated stellar parameters for 90 transit hosts. The effect of the surface gravity. Astron. Astrophys. 558, A106 (2013).

    Article  Google Scholar 

  43. Asplund, M., Grevesse, N., Sauval, A. J. & Scott, P. The chemical composition of the Sun. Annu. Rev. Astron. Astrophys. 47, 481–522 (2009).

    Article  ADS  Google Scholar 

  44. Weiss, A. & Schlattl, H. GARSTEC—the Garching Stellar Evolution Code. The direct descendant of the legendary Kippenhahn code. Astrophys. Space Sci. 316, 99–106 (2008).

    Article  ADS  Google Scholar 

  45. Christensen-Dalsgaard, J. ADIPLS—the Aarhus adiabatic oscillation package. Astrophys. Space Sci. 316, 113–120 (2008).

    Article  ADS  Google Scholar 

  46. Thoul, A. A., Bahcall, J. N. & Loeb, A. Element diffusion in the solar interior. Astrophys. J. 421, 828–842 (1994).

    Article  ADS  Google Scholar 

  47. Freytag, B., Ludwig, H.-G. & Steffen, M. Hydrodynamical models of stellar convection. The role of overshoot in DA white dwarfs, A-type stars, and the Sun. Astron. Astrophys. 313, 497–516 (1996).

    ADS  Google Scholar 

  48. Kjeldsen, H., Bedding, T. R. & Christensen-Dalsgaard, J. Correcting stellar oscillation frequencies for near-surface effects. Astrophys. J. Lett. 683, L175 (2008).

    Article  ADS  Google Scholar 

  49. Silva Aguirre, V. et al. Stellar ages and convective cores in field main-sequence stars: first asteroseismic application to two Kepler targets. Astrophys. J. 769, 141 (2013).

    Article  ADS  Google Scholar 

  50. Pepe, F. et al. The CORALIE survey for southern extra-solar planets VII. Two short-period Saturnian companions to HD 108147 and HD 168746. Astron. Astrophys. 388, 632–638 (2002).

    Article  ADS  Google Scholar 

  51. Malavolta, L. et al. The Kepler-19 system: a thick-envelope super-Earth with two Neptune-mass companions characterized using radial velocities and transit timing variations. Astron. J. 153, 224 (2017).

    Article  ADS  Google Scholar 

  52. Boisse, I. et al. Disentangling between stellar activity and planetary transits. Astron. Astrophys. 528, A4 (2011).

    Article  Google Scholar 

  53. Noyes, R. W., Hartmann, L. W., Baliunas, S. L., Duncan, D. K. & Vaughan, A. H. Rotation, convection, and magnetic activity in lower main-sequence stars. Astrophys. J. 279, 763–777 (1984).

    Article  ADS  Google Scholar 

  54. Zechmeister, M. & Kürster, M. The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms. Astron. Astrophys. 496, 577–584 (2009).

    Article  ADS  Google Scholar 

  55. Gregory, P. C. A Bayesian analysis of extrasolar planet data for HD 73526. Astrophys. J. 631, 1198–1214 (2005).

    Article  ADS  Google Scholar 

  56. Matsumura, S., Takeda, G. & Rasio, F. A. On the origins of eccentric close-in planets. Astrophys. J. Lett. 686, L29 (2008).

    Article  ADS  Google Scholar 

  57. Lainey, V. Quantification of tidal parameters from Solar System data. Celest. Mech. Dyn. Astr. 126, 145–156 (2016).

    Article  ADS  Google Scholar 

  58. Chambers, J. E. A hybrid symplectic integrator that permits close encounters between massive bodies. Mon. Not. R. Astron. Soc. 304, 793–799 (1999).

    Article  ADS  Google Scholar 

  59. Eastman, J., Gaudi, B. S. & Agol, E. EXOFAST: a fast exoplanetary fitting suite in IDL. Publ. Astron. Soc.Pacif. 125, 83 (2013).

    Article  ADS  Google Scholar 

  60. Haywood, R. et al. Planets and stellar activity: hide and seek in the CoRoT-7 system. Mon. Not. R. Astron. Soc. 443, 2517–2531 (2014).

    Article  ADS  Google Scholar 

  61. Feroz, F., Hobson, M. P., Cameron, E. & Pettitt, A. N. Importance nested sampling and the MultiNest algorithm. Preprint at https://arxiv.org/abs/1306.2144 (2014).

  62. Buchner, J. et al. X-ray spectral modelling of the AGN obscuring region in the CDFS: Bayesian model selection and catalogue. Astron. Astrophys. 564, A125 (2014).

    Article  Google Scholar 

  63. Kass, R. E. & Raftery, A. E. Bayes factors. J. Am. Stat. Assoc. 90, 773–795 (1995).

    Article  MathSciNet  Google Scholar 

  64. Xie, J.-W. et al. Exoplanet orbital eccentricities derived from LAMOST-Kepler analysis. Proc. Natl Acad. Sci. USA 113, 11431–11435 (2016).

    Article  ADS  Google Scholar 

  65. Borsato, L. et al. TRADES: a new software to derive orbital parameters from observed transit times and radial velocities. Revisiting Kepler-11 and Kepler-9. Astron. Astrophys. 571, A38 (2014).

    Article  Google Scholar 

  66. Bonomo, A. S. et al. Improved parameters of seven Kepler giant companions characterized with SOPHIE and HARPS-N. Astron. Astrophys. 575, A85 (2015).

    Article  Google Scholar 

  67. Mandel, K. & Agol, E. Analytic light curves for planetary transit searches. Astrophys. J. 580, L171–L175 (2002).

    Article  ADS  Google Scholar 

  68. Kipping, D. Efficient, uninformative sampling of limb darkening coefficients for two-parameter laws. Mon. Not. R. Astron. Soc. 435, 2152–2160 (2013).

    Article  ADS  Google Scholar 

  69. Claret, A. Testing the limb-darkening coefficients measured from eclipsing binaries. Astron. Astrophys. 482, 259–266 (2008).

    Article  ADS  Google Scholar 

  70. Fogtmann-Schulz, A. et al. Accurate parameters of the oldest known rocky-exoplanet hosting system: Kepler-10 revisited. Astrophys. J. 781, 67 (2014).

    Article  ADS  Google Scholar 

  71. Lithwick, Y., Xie, J. & Wu, Y. Extracting planet mass and eccentricity from TTV data. Astrophys. J. 761, 122 (2012).

    Article  ADS  Google Scholar 

  72. Mills, S. M. et al. A resonant chain of four transiting, sub-Neptune planets. Nature 533, 509–512 (2016).

    Article  ADS  Google Scholar 

  73. Brugger, B., Mousis, O., Deleuil, M. & Deschamps, F. Constraints on super-Earth interiors from stellar abundances. Astrophys. J. 850, 93 (2017).

    Article  ADS  Google Scholar 

  74. Grossman, L. Condensation in the primitive solar nebula. Geochim. Cosmochim. Acta 36, 597–619 (1972).

    Article  ADS  Google Scholar 

  75. Lopez, E. D. Born dry in the photoevaporation desert: Kepler’s ultra-short-period planets formed water-poor. Mon. Not. R. Astron. Soc. 472, 245–253 (2011).

    Article  ADS  Google Scholar 

  76. Miguel, Y., Kaltenegger, L., Fegley, B. & Schaefer, L. Compositions of hot super-Earth atmospheres: exploring Kepler candidates. Astrophys. J. Lett. 742, L19 (2011).

    Article  ADS  Google Scholar 

  77. Kite, E. S., Fegley, B. Jr, Schaefer, L. & Gaidos, E. Atmosphere-interior exchange on hot, rocky exoplanets. Astrophys. J. 828, 80 (2016).

    Article  ADS  Google Scholar 

  78. Schlichting, H. E., Sari, R. & Yalinewich, A. Atmospheric mass loss during planet formation: the importance of planetesimal impacts. Icarus 247, 81–94 (2015).

    Article  ADS  Google Scholar 

  79. Zahnle, K. J. & Catling, D. C. The cosmic shoreline: the evidence that escape determines which planets have atmospheres, and what this may mean for Proxima Centauri B. Astrophys. J. 828, 80 (2017).

    Google Scholar 

  80. Springel, V. The cosmological simulation code GADGET-2. Mon. Not. R. Astron. Soc. 364, 1105–1134 (2005).

    Article  ADS  Google Scholar 

  81. Ćuk, M. & Stewart, S. T. Making the moon from a fast-spinning Earth: a giant impact followed by resonant despinning. Science 338, 1047–1052 (2012).

    Article  ADS  Google Scholar 

  82. Valencia, D., O’Connell, R. J. & Sasselov, D. Internal structure of massive terrestrial planets. Icarus 181, 545–555 (2006).

    Article  ADS  Google Scholar 

  83. Benz, W. & Asphaug, E. Catastrophic disruptions revisited. Icarus 142, 5–20 (1999).

    Article  ADS  Google Scholar 

Download references

Acknowledgements

The authors wish to thank R. D. Haywood, R. Silvotti and D. Charbonneau for useful discussions. The HARPS-N project was funded by the Prodex Program of the Swiss Space Office (SSO), the Harvard-University Origin of Life Initiative (HUOLI), the Scottish Universities Physics Alliance (SUPA), the University of Geneva, the Smithsonian Astrophysical Observatory (SAO), the Italian National Astrophysical Institute (INAF), University of St. Andrews, Queen’s University Belfast and University of Edinburgh. The present work is based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundación Galileo Galilei of the INAF (Istituto Nazionale di AstroFisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. This paper exploited data collected by the Kepler mission; funding for the Kepler mission is provided by the NASA (National Aeronautics and Space Administration) Science Mission directorate. The research leading to these results received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement number 313014 (ETAEARTH). L.Z. acknowledges support from the Simons Foundation (SCOL (award no. 337090)). M.D. acknowledges financial support from Progetto Premiale 2015 FRONTIERA funding scheme of the Italian Ministry of Education, University, and Research. Funding for the Stellar Astrophysics Centre is provided by The Danish National Research Foundation (grant agreement no. DNRF106). V.S.A. acknowledges support from VILLUM FONDEN (research grant 10118). E.C. is funded by the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement no. 664931. T.D. is supported by a STFC PhD studentship. R.A.G. acknowledges support from CNES. This work has been carried out in the frame of the National Centre for Competence in Research PlanetS supported by the Swiss National Science Foundation (SNSF). C.L., F.B., F.P. and S.U. acknowledge the financial support of the SNSF. M.S.L. is supported by The Independent Research Fund Denmark’s Sapere Aude program (grant agreement no. DFF–5051–00130). S.M. acknowledges support from the Ramon y Cajal fellowship number RYC-2015–17697.

Author information

Authors and Affiliations

  1. INAF–Osservatorio Astrofisico di Torino, Pino Torinese, Italy

    Aldo S. Bonomo, Mario Damasso & Alessandro Sozzetti

  2. Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA

    Li Zeng

  3. School of Physics, University of Bristol, HH Wills Physics Laboratory, Bristol, UK

    Zoë M. Leinhardt & Thomas Denman

  4. Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Aarhus C, Denmark

    Anders B. Justesen, Mikkel N. Lund, Victor Silva Aguirre, Torben Arentoft, Jørgen Christensen-Dalsgaard, Rasmus Handberg, Hans Kjeldsen & Mia S. Lundkvist

  5. NASA Goddard Space Flight Center, Greenbelt, MD, USA

    Eric Lopez

  6. Dipartimento di Fisica e Astronomia “Galileo Galilei”, Università di Padova, Padua, Italy

    Luca Malavolta, Valerio Nascimbeni & Giampaolo Piotto

  7. INAF—Osservatorio Astronomico di Padova, Padua, Italy

    Luca Malavolta, Valerio Nascimbeni & Giampaolo Piotto

  8. DTU Space, National Space Institute, Technical University of Denmark, Kongens Lyngby, Denmark

    Lars A. Buchhave

  9. INAF - Osservatorio Astrofisico di Catania, Catania, Italy

    Enrico Corsaro

  10. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA

    Mercedes Lopez-Morales, Andrew Vanderburg, John A. Johnson, David W. Latham, Chantanelle Nava, David F. Phillips & Dimitar Sasselov

  11. The Department of Astronomy, The California Institute of Technology, Pasadena, CA, USA

    Sean M. Mills

  12. Centre for Exoplanet Science, SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, UK

    Annelies Mortier & Andrew Collier Cameron

  13. SUPA, Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, UK

    Ken Rice

  14. Department of Astronomy, The University of Texas at Austin, Austin, TX, USA

    Andrew Vanderburg

  15. INAF—Osservatorio Astronomico di Palermo, Palermo, Italy

    Laura Affer & Giusi Micela

  16. IRFU, CEA, Université Paris-Saclay, Gif-sur-Yvette, France

    Mansour Benbakoura & Rafael A. García

  17. Université Paris Diderot, AIM, Sorbonne Paris Cité, CEA, CNRS, Gif-sur-Yvette, France

    Mansour Benbakoura & Rafael A. García

  18. Observatoire Astronomique de l’Université de Genève, Versoix, Switzerland

    François Bouchy, Xavier Dumusque, Christophe Lovis, Michel Mayor, Fatemeh Motalebi, Francesco Pepe, Damien Ségransan & Stéphane Udry

  19. INAF—Fundación Galileo Galilei, Breña Baja, Spain

    Rosario Cosentino, Aldo F. M. Fiorenzano, Avet Harutyunyan & Ennio Poretti

  20. Astronomy Department, University of California Berkeley, Berkeley, CA, USA

    Courtney D. Dressing

  21. European Southern Observatory, Vitacura, Chile

    Pedro Figueira

  22. Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP, Porto, Portugal

    Pedro Figueira

  23. Zentrum für Astronomie der Universität Heidelberg, Heidelberg, Germany

    Mia S. Lundkvist

  24. Departamento de Astrofísica, Universidad de La Laguna, Tenerife, Spain

    Savita Mathur

  25. Instituto de Astrofísica de Canarias, La Laguna, Tenerife, Spain

    Savita Mathur

  26. INAF—Osservatorio Astronomico di Cagliari, Selargius, Italy

    Emilio Molinari

  27. INAF – Osservatorio Astronomico di Brera, Merate, Italy

    Ennio Poretti

  28. Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast, UK

    Chris Watson

Authors
  1. Aldo S. Bonomo
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Li Zeng
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Mario Damasso
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Zoë M. Leinhardt
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Anders B. Justesen
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Eric Lopez
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Mikkel N. Lund
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Luca Malavolta
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Victor Silva Aguirre
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Lars A. Buchhave
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Enrico Corsaro
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. Thomas Denman
    View author publications

    You can also search for this author in PubMed Google Scholar

  13. Mercedes Lopez-Morales
    View author publications

    You can also search for this author in PubMed Google Scholar

  14. Sean M. Mills
    View author publications

    You can also search for this author in PubMed Google Scholar

  15. Annelies Mortier
    View author publications

    You can also search for this author in PubMed Google Scholar

  16. Ken Rice
    View author publications

    You can also search for this author in PubMed Google Scholar

  17. Alessandro Sozzetti
    View author publications

    You can also search for this author in PubMed Google Scholar

  18. Andrew Vanderburg
    View author publications

    You can also search for this author in PubMed Google Scholar

  19. Laura Affer
    View author publications

    You can also search for this author in PubMed Google Scholar

  20. Torben Arentoft
    View author publications

    You can also search for this author in PubMed Google Scholar

  21. Mansour Benbakoura
    View author publications

    You can also search for this author in PubMed Google Scholar

  22. François Bouchy
    View author publications

    You can also search for this author in PubMed Google Scholar

  23. Jørgen Christensen-Dalsgaard
    View author publications

    You can also search for this author in PubMed Google Scholar

  24. Andrew Collier Cameron
    View author publications

    You can also search for this author in PubMed Google Scholar

  25. Rosario Cosentino
    View author publications

    You can also search for this author in PubMed Google Scholar

  26. Courtney D. Dressing
    View author publications

    You can also search for this author in PubMed Google Scholar

  27. Xavier Dumusque
    View author publications

    You can also search for this author in PubMed Google Scholar

  28. Pedro Figueira
    View author publications

    You can also search for this author in PubMed Google Scholar

  29. Aldo F. M. Fiorenzano
    View author publications

    You can also search for this author in PubMed Google Scholar

  30. Rafael A. García
    View author publications

    You can also search for this author in PubMed Google Scholar

  31. Rasmus Handberg
    View author publications

    You can also search for this author in PubMed Google Scholar

  32. Avet Harutyunyan
    View author publications

    You can also search for this author in PubMed Google Scholar

  33. John A. Johnson
    View author publications

    You can also search for this author in PubMed Google Scholar

  34. Hans Kjeldsen
    View author publications

    You can also search for this author in PubMed Google Scholar

  35. David W. Latham
    View author publications

    You can also search for this author in PubMed Google Scholar

  36. Christophe Lovis
    View author publications

    You can also search for this author in PubMed Google Scholar

  37. Mia S. Lundkvist
    View author publications

    You can also search for this author in PubMed Google Scholar

  38. Savita Mathur
    View author publications

    You can also search for this author in PubMed Google Scholar

  39. Michel Mayor
    View author publications

    You can also search for this author in PubMed Google Scholar

  40. Giusi Micela
    View author publications

    You can also search for this author in PubMed Google Scholar

  41. Emilio Molinari
    View author publications

    You can also search for this author in PubMed Google Scholar

  42. Fatemeh Motalebi
    View author publications

    You can also search for this author in PubMed Google Scholar

  43. Valerio Nascimbeni
    View author publications

    You can also search for this author in PubMed Google Scholar

  44. Chantanelle Nava
    View author publications

    You can also search for this author in PubMed Google Scholar

  45. Francesco Pepe
    View author publications

    You can also search for this author in PubMed Google Scholar

  46. David F. Phillips
    View author publications

    You can also search for this author in PubMed Google Scholar

  47. Giampaolo Piotto
    View author publications

    You can also search for this author in PubMed Google Scholar

  48. Ennio Poretti
    View author publications

    You can also search for this author in PubMed Google Scholar

  49. Dimitar Sasselov
    View author publications

    You can also search for this author in PubMed Google Scholar

  50. Damien Ségransan
    View author publications

    You can also search for this author in PubMed Google Scholar

  51. Stéphane Udry
    View author publications

    You can also search for this author in PubMed Google Scholar

  52. Chris Watson
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

The underlying radial-velocity observation programme was conceived and organized by F.P., A.C.C., D.W.L., C.L., D.Ségransan, S.U. and E.M. Observations with HARPS-N were carried out by L.A., A.C.C., A.M., C.D.D., M.D., X.D., R.C., A.F.M.F., P.F., A.H., F.M., M.L.-M., L.M., C.N., V.N., K.R. and A.V. C.L. maintained and updated the reduction pipeline, L.M. implemented the correction of radial velocities for moonlight contamination, and X.D. computed the values of the log(R’HK) activity indicator. A.S.B., M.D. and K.R. analysed and modelled the radial velocities. L.M. simulated and compared the radial velocities using both non-interacting and interacting Keplerians. A.S.B. also performed the transit fitting and S.M.M. worked on the analysis of transit timing variations. A.S.B. and A.V. analysed the Kepler light curve in search of the stellar rotational modulation signal. L.B. and A.M. determined the stellar atmospheric parameters from the HARPS-N spectra; A.M. also derived the stellar chemical abundances. T.A., M.B., E.C., J.C.-D., R.A.G., R.H., A.B.J., H.K., M.N.L., M.S.L., S.M. and V.S.A. carried out the asteroseismic analysis of the Kepler light curve and determined the stellar parameters from which A.S.B. and M.D. derived the planetary orbital and physical parameters. L.Z. deduced the planet interior compositions and E.L. estimated the planet atmospheric escapes. K.R. carried out dynamical simulations of the planetary system, and Z.M.L. and T.D. conducted the simulations of giant impact events. A.S.B. was the primary author of the manuscript and received important contributions by L.Z., Z.M.L., M.D., E.L., M.N.L., V.S.A., A.S., A.M. and M.L.-M. All authors have contributed to the interpretation of the data and the results.

Corresponding author

Correspondence to Aldo S. Bonomo.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Figures 1–8, Supplementary Tables 1–4.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Bonomo, A.S., Zeng, L., Damasso, M. et al. A giant impact as the likely origin of different twins in the Kepler-107 exoplanet system. Nat Astron 3, 416–423 (2019). https://doi.org/10.1038/s41550-018-0684-9

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41550-018-0684-9

This article is cited by

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