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A remnant planetary core in the hot-Neptune desert

Abstract

The interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors. Planets found in and near the typically barren hot-Neptune ‘desert’1,2 (a region in mass–radius space that contains few planets) have proved to be particularly valuable in this regard. These planets include HD149026b3, which is thought to have an unusually massive core, and recent discoveries such as LTT9779b4 and NGTS-4b5, on which photoevaporation has removed a substantial part of their outer atmospheres. Here we report observations of the planet TOI-849b, which has a radius smaller than Neptune’s but an anomalously large mass of \(39.1{\,}_{-2.6}^{+2.7}\) Earth masses and a density of \(5.2{\,}_{-0.8}^{+0.7}\) grams per cubic centimetre, similar to Earth’s. Interior-structure models suggest that any gaseous envelope of pure hydrogen and helium consists of no more than \({3.9}_{-0.9}^{+0.8}\) per cent of the total planetary mass. The planet could have been a gas giant before undergoing extreme mass loss via thermal self-disruption or giant planet collisions, or it could have avoided substantial gas accretion, perhaps through gap opening or late formation6. Although photoevaporation rates cannot account for the mass loss required to reduce a Jupiter-like gas giant, they can remove a small (a few Earth masses) hydrogen and helium envelope on timescales of several billion years, implying that any remaining atmosphere on TOI-849b is likely to be enriched by water or other volatiles from the planetary interior. We conclude that TOI-849b is the remnant core of a giant planet.

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Fig. 1: Best-fitting model to the TESS, HARPS and NGTS data.
Fig. 2: Mass–radius diagram of known exoplanets from the NASA exoplanet archive.
Fig. 3: TOI-849b in the context of the hot-Neptune desert.

Data availability

TESS data are publicly available at MAST (https://archive.stsci.edu/missions-and-data/transiting-exoplanet-survey-satellite-tess). The HARPS data used in this study are available within the paper or the Supplementary Information files and were collected under ESO programme ID 1102.C-0249. The NGTS (Data Tags 19249 and 19250), LCOGT (Data Tags 5106 and 5386) and specific detrended TESS light curve (Data Tag 19248) used in this work are available via the Exofop-TESS archive (https://exofop.ipac.caltech.edu/tess/).

Code availability

The PASTIS code has been published previously11,59. The latest version of the ARES code (ARES v2) is available at http://www.astro.up.pt/~sousasag/ares.

References

  1. Szabó, G. M. & Kiss, L. L. A short-period censor of sub-Jupiter mass exoplanets with low density. Astrophys. J. Lett. 727, L44 (2011).

    ADS  Google Scholar 

  2. Owen, J. E. & Lai, D. Photoevaporation and high-eccentricity migration created the sub-Jovian desert. Mon. Not. R. Astron. Soc. 479, 5012–5021 (2018).

    ADS  CAS  Google Scholar 

  3. Sato, B. et al. The N2K Consortium. II. A transiting hot Saturn around HD 149026 with a large dense core. Astrophys. J. 633, 465–473 (2005).

    ADS  Google Scholar 

  4. Jenkins, J. TESS Discovery of the first ultra hot Neptune, LTT9779b. In AAS/Division for Extreme Solar Systems Abstracts Vol. 51, 103.07 (American Astronomical Society, 2019).

  5. West, R. G. et al. NGTS-4b: a sub-Neptune transiting in the desert. Mon. Not. R. Astron. Soc. 486, 5094–5103 (2019).

    ADS  CAS  Google Scholar 

  6. Lee, E. J. The boundary between gas-rich and gas-poor planets. Astrophys. J. 878, 36 (2019).

    ADS  CAS  Google Scholar 

  7. Ricker, G. R. et al. Transiting exoplanet survey satellite (TESS). J. Astron. Telesc. Instrum. Syst. 1, 014003 (2014).

    ADS  Google Scholar 

  8. Wheatley, P. J. et al. The next generation transit survey (NGTS). Mon. Not. R. Astron. Soc. 475, 4476–4493 (2018).

    ADS  CAS  Google Scholar 

  9. Brown, T. M. et al. Las Cumbres Observatory global telescope network. Publ. Astron. Soc. Pacific 125, 1031 (2013).

    ADS  Google Scholar 

  10. Gaia Collaboration. Gaia Data Release 2. Summary of the contents and survey properties. Astron. Astrophys. 616, A1 (2018).

    Google Scholar 

  11. Santerne, A. et al. PASTIS: Bayesian extrasolar planet validation - II. Constraining exoplanet blend scenarios using spectroscopic diagnoses. Mon. Not. R. Astron. Soc. 451, 2337–2351 (2015).

    ADS  Google Scholar 

  12. Bodenheimer, P., Stevenson, D. J., Lissauer, J. J. & D’Angelo, G. New formation models for the Kepler-36 system. Astrophys. J. 868, 138 (2018).

    ADS  CAS  Google Scholar 

  13. Dorn, C. et al. A generalized Bayesian inference method for constraining the interiors of super Earths and sub-Neptunes. Astron. Astrophys. 597, A37 (2017).

    Google Scholar 

  14. Mizuno, H., Nakazawa, K. & Hayashi, C. Instability of a gaseous envelope surrounding a planetary core and formation of giant planets. Prog. Theor. Phys. 60, 699–710 (1978).

    ADS  CAS  Google Scholar 

  15. Rafikov, R. R. Atmospheres of protoplanetary cores: critical mass for nucleated instability. Astrophys. J. 648, 666–682 (2006).

    ADS  Google Scholar 

  16. Piso, A.-M. A., Youdin, A. N. & Murray-Clay, R. A. Minimum core masses for giant planet formation with realistic equations of state and opacities. Astrophys. J. 800, 82 (2015).

    ADS  Google Scholar 

  17. Stassun, K. G., Collins, K. A. & Gaudi, B. S. Accurate empirical radii and masses of planets and their host stars with gaia parallaxes. Astron. J. 153, 136 (2017).

    ADS  Google Scholar 

  18. Fortney, J. J., Saumon, D., Marley, M. S., Lodders, K. & Freedman, R. S. Atmosphere, interior, and evolution of the metal-rich transiting planet HD 149026b. Astrophys. J. 642, 495–504 (2006).

    ADS  CAS  Google Scholar 

  19. Ikoma, M., Guillot, T., Genda, H., Tanigawa, T. & Ida, S. On the origin of HD 149026b. Astrophys. J. 650, 1150–1159 (2006).

    ADS  CAS  Google Scholar 

  20. Delrez, L. et al. WASP-121 b: a hot Jupiter close to tidal disruption transiting an active F star. Mon. Not. R. Astron. Soc. 458, 4025–4043 (2016).

    ADS  CAS  Google Scholar 

  21. Collier Cameron, A. & Jardine, M. Hierarchical Bayesian calibration of tidal orbit decay rates among hot Jupiters. Mon. Not. R. Astron. Soc. 476, 2542–2555 (2018).

    ADS  Google Scholar 

  22. Hamer, J. H. & Schlaufman, K. C. Hot Jupiters are destroyed by tides while their host stars are on the main sequence. Astron. J. 158, 190 (2019).

    ADS  CAS  Google Scholar 

  23. Winn, J. N. et al. Absence of a metallicity effect for ultra-short-period planets. Astron. J. 154, 60 (2017).

    ADS  Google Scholar 

  24. Iaroslavitz, E. & Podolak, M. Atmospheric mass deposition by captured planetesimals. Icarus 187, 600–610 (2007).

    ADS  CAS  Google Scholar 

  25. Brouwers, M. G., Vazan, A. & Ormel, C. W. How cores grow by pebble accretion. I. Direct core growth. Astron. Astrophys. 611, A65 (2018).

    ADS  Google Scholar 

  26. Mordasini, C. in Handbook of Exoplanets (ed. Pudritz, R.) 2425–2474 (Springer, 2018).

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

    ADS  Google Scholar 

  28. Duffell, P. C. & MacFadyen, A. I. Gap opening by extremely low-mass planets in a viscous disk. Astrophys. J. 769, 41 (2013).

    ADS  Google Scholar 

  29. Triaud, A. H. M. J. in Handbook of Exoplanets (eds Deeg, H. & Belmonte, J.) 1375–1401 (Springer, 2018).

  30. Xie, J.-W. Transit timing variation of near-resonance planetary pairs. II. Confirmation of 30 planets in 15 multiple-planet systems. Astrophys. J. Suppl. Ser. 210, 25 (2014).

    ADS  Google Scholar 

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

    ADS  Google Scholar 

  32. Jenkins, J. M. et al. The TESS science processing operations center. In Proc. SPIE Software and Cyberinfrastructure for Astronomy IV Series, Vol. 9913, 99133 (SPIE, 2016).

  33. Huang, X. et al. A quick look into the first discoveries of TESS. In American Astronomical Society Meeting Abstracts Vol. 233, 209.08 (American Astronomical Society, 2019).

  34. Vanderburg, A. & Johnson, J. A. A technique for extracting highly precise photometry for the two-wheeled Kepler mission. Publ. Astron. Soc. Pacific 126, 948 (2014).

    ADS  Google Scholar 

  35. Armstrong, D. J. et al. K2 variable catalogue: variable stars and eclipsing binaries in K2 campaigns 1 and 0. Astron. Astrophys. 579, A19 (2015).

    Google Scholar 

  36. McCormac, J. et al. DONUTS: a science frame autoguiding algorithm with sub-pixel precision, capable of guiding on defocused stars. Publ. Astron. Soc. Pacific 125, 548 (2013).

    ADS  Google Scholar 

  37. Mayor, M. et al. Setting new standards with HARPS. Messenger 114, 20–24 (2003).

    ADS  Google Scholar 

  38. Baranne, A. et al. ELODIE: a spectrograph for accurate radial velocity measurements. Astron. Astrophys. Suppl. Ser. 119, 373–390 (1996).

    ADS  Google Scholar 

  39. Pepe, F. et al. HARPS: ESO’s coming planet searcher. Chasing exoplanets with the La Silla 3.6-m telescope. Messenger 110, 9–14 (2002).

    ADS  Google Scholar 

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

    Google Scholar 

  41. Jensen, E. Tapir: A web interface for transit/eclipse observability. Astrophysics Source Code Library 1306.007 (2013).

    Google Scholar 

  42. Collins, K. A., Kielkopf, J. F., Stassun, K. G. & Hessman, F. V. AstroImageJ: image processing and photometric extraction for ultra-precise astronomical light curves. Astron. J. 153, 77 (2017).

    ADS  Google Scholar 

  43. Tokovinin, A. Ten years of speckle interferometry at SOAR. Publ. Astron. Soc. Pacific 130, 035002 (2018).

    ADS  Google Scholar 

  44. Ziegler, C. et al. SOAR TESS Survey. I: sculpting of TESS planetary systems by stellar companions. Astron. J. 159, 19 (2019).

    ADS  Google Scholar 

  45. Hormuth, F., Brandner, W., Hippler, S. & Henning, T. AstraLux – the Calar Alto 2.2-m telescope LuckyImaging camera. J. Phys. Conf. Ser. 131, 012051 (2008).

    Google Scholar 

  46. Fried, D. L. Probability of getting a lucky short-exposure image through turbulence. J. Opt. Soc. Am. 68, 1651–1658 (1978).

    ADS  Google Scholar 

  47. Strehl, K. Über die Bildschärfe der Fernrohre. Astron. Nachr. 158, 89–90 (1902).

    ADS  Google Scholar 

  48. Lillo-Box, J., Barrado, D. & Bouy, H. Multiplicity in transiting planet-host stars. A lucky imaging study of Kepler candidates. Astron. Astrophys. 546, A10 (2012).

    ADS  Google Scholar 

  49. Lillo-Box, J., Barrado, D. & Bouy, H. High-resolution imaging of Kepler planet host candidates. A comprehensive comparison of different techniques. Astron. Astrophys. 566, A103 (2014).

    ADS  Google Scholar 

  50. Howell, S. B., Everett, M. E., Sherry, W., Horch, E. & Ciardi, D. R. Speckle camera observations for the NASA Kepler Mission Follow-up Program. Astron. J.142, 19 (2011).

    ADS  Google Scholar 

  51. Sousa, S. G. et al. A new procedure for defining a homogenous line-list for solar-type stars. Astron. Astrophys. 561, A21 (2014).

    Google Scholar 

  52. Santos, N. C. et al. SWEET-Cat: a catalogue of parameters for Stars With ExoplanETs. I. New atmospheric parameters and masses for 48 stars with planets. Astron. Astrophys. 556, A150 (2013).

    Google Scholar 

  53. Sousa, S. G., Santos, N. C., Israelian, G., Mayor, M. & Monteiro, M. J. P. F. G. A new code for automatic determination of equivalent widths: Automatic Routine for line Equivalent widths in stellarSpectra (ARES). Astron. Astrophys. 469, 783–791 (2007).

    ADS  Google Scholar 

  54. Sousa, S. G., Santos, N. C., Adibekyan, V., Delgado-Mena, E. & Israelian, G. ARES v2: new features and improved performance. Astron. Astrophys. 577, A67 (2015).

    ADS  Google Scholar 

  55. Kurucz, R. L. SYNTHE Spectrum Synthesis Programs and Line Data CD-ROM (Smithsonian Astrophysical Observatory, 1993).

  56. Sneden, C. A. Carbon and Nitrogen Abundances in Metal-Poor Stars. PhD thesis, Univ. of Texas at Austin (1973).

  57. Adibekyan, V. Z. et al. Chemical abundances and kinematics of 257 G-, K-type field giants. Setting a base for further analysis of giant-planet properties orbiting evolved stars. Mon. Not. R. Astron. Soc. 450, 1900–1915 (2015).

    ADS  CAS  Google Scholar 

  58. Adibekyan, V. Z. et al. Chemical abundances of 1111 FGK stars from the HARPS GTO planet search program. Galactic stellar populations and planets. Astron. Astrophys. 545, A32 (2012).

    Google Scholar 

  59. Díaz, R. F. et al. PASTIS: Bayesian extrasolar planet validation – I. General framework, models, and performance. Mon. Not. R. Astron. Soc. 441, 983–1004 (2014).

    ADS  Google Scholar 

  60. Henden, A. A., Levine, S., Terrell, D. & Welch, D. L. APASS – the latest data release. In American Astronomical Society Meeting Abstracts Vol. 225, 336.16 (2015).

  61. Munari, U. et al. APASS Landolt-Sloan BVgri photometry of RAVE Stars. I. Data, effective temperatures, and reddenings. Astron. J. 148, 81 (2014).

    ADS  Google Scholar 

  62. Cutri, R. M. & et al. VizieR Online Data Catalog: AllWISE Data Release (Cutri+ 2013) 2328 http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=II/328 (2014).

  63. Southworth, J. Homogeneous studies of transiting extrasolar planets - I. Light-curve analyses. Mon. Not. R. Astron. Soc. 386, 1644–1666 (2008).

    ADS  CAS  Google Scholar 

  64. Kipping, D. M. Binning is sinning: morphological light-curve distortions due to finite integration time. Mon. Not. R. Astron. Soc. 408, 1758–1769 (2010).

    ADS  Google Scholar 

  65. Allard, F., Homeier, D. & Freytag, B. Models of very-low-mass stars, brown dwarfs and exoplanets. Philos. Trans. Royal Soc. A 370, 2765–2777 (2012).

    ADS  CAS  Google Scholar 

  66. Dotter, A. et al. The Dartmouth stellar evolution database. Astrophys. J. Suppl. Ser. 178, 89–101 (2008).

    ADS  CAS  Google Scholar 

  67. Kipping, D. M. Characterizing distant worlds with asterodensity profiling. Mon. Not. R. Astron. Soc. 440, 2164–2184 (2014).

    ADS  Google Scholar 

  68. Schönrich, R., McMillan, P. & Eyer, L. Distances and parallax bias in Gaia DR2. Mon. Not. R. Astron. Soc. 487, 3568–3580 (2019).

    ADS  Google Scholar 

  69. Van Eylen, V. et al. The orbital eccentricity of small planet systems. Astron. J. 157, 61 (2019).

    ADS  Google Scholar 

  70. Claret, A. & Bloemen, S. Gravity and limb-darkening coefficients for the Kepler, CoRoT, Spitzer, uvby, UBVRIJHK, and Sloan photometric systems. Astron. Astrophys. 529, A75 (2011).

    ADS  Google Scholar 

  71. Stassun, K. G. & Torres, G. Eclipsing binaries as benchmarks for trigonometric parallaxes in the Gaia era. Astron. J. 152, 180 (2016).

    ADS  Google Scholar 

  72. Stassun, K. G., Corsaro, E., Pepper, J. A. & Gaudi, B. S. Empirical accurate masses and radii of single stars with TESS and Gaia. Astron. J. 155, 22 (2018).

    ADS  Google Scholar 

  73. Schlegel, D. J., Finkbeiner, D. P. & Davis, M. Maps of dust infrared emission for use in estimation of reddening and cosmic microwave background radiation foregrounds. Astrophys. J. 500, 525–553 (1998).

    ADS  Google Scholar 

  74. Stassun, K. G. & Torres, G. Evidence for a systematic offset of −80 μas in the Gaia DR2 parallaxes. Astrophys. J. 862, 61 (2018).

    ADS  Google Scholar 

  75. Torres, G., Andersen, J. & Giménez, A. Accurate masses and radii of normal stars: modern results and applications. Astron. Astrophys. 18, 67–126 (2010).

    ADS  Google Scholar 

  76. Hakim, K. et al. A new ab initio equation of state of hcp-Fe and its implication on the interior structure and mass-radius relations of rocky super-Earths. Icarus 313, 61–78 (2018).

    ADS  CAS  Google Scholar 

  77. Connolly, J. A. D. The geodynamic equation of state: what and how. Geochem. Geophys. Geosyst. 10, Q10014 (2009).

    ADS  Google Scholar 

  78. Vazan, A., Kovetz, A., Podolak, M. & Helled, R. The effect of composition on the evolution of giant and intermediate-mass planets. Mon. Not. R. Astron. Soc. 434, 3283–3292 (2013).

    ADS  Google Scholar 

  79. Seager, S., Kuchner, M., Hier-Majumder, C. A. & Militzer, B. Mass–radius relationships for solid exoplanets. Astrophys. J. 669, 1279–1297 (2007).

    ADS  CAS  Google Scholar 

  80. Saumon, D., Chabrier, G. & van Horn, H. M. An equation of state for low-mass stars and giant planets. Astrophys. J. S 99, 713 (1995).

    ADS  CAS  Google Scholar 

  81. Dorn, C. et al. Can we constrain the interior structure of rocky exoplanets from mass and radius measurements? Astron. Astrophys. 577, A83 (2015).

    Google Scholar 

  82. Lozovsky, M., Helled, R., Rosenberg, E. D. & Bodenheimer, P. Jupiter’s formation and its primordial internal structure. Astrophys. J. 836, 227 (2017).

    ADS  Google Scholar 

  83. Lozovsky, M., Helled, R., Dorn, C. & Venturini, J. Threshold radii of volatile-rich planets. Astrophys. J. 866, 49 (2018).

    ADS  Google Scholar 

  84. Lammer, H. et al. Atmospheric loss of exoplanets resulting from stellar X-Ray and extreme-ultraviolet heating. Astrophys. J. Lett. 598, 121–124 (2003).

    ADS  Google Scholar 

  85. Jackson, A. P., Davis, T. A. & Wheatley, P. J. The coronal X-ray-age relation and its implications for the evaporation of exoplanets. Mon. Not. R. Astron. Soc. 422, 2024–2043 (2012).

    ADS  Google Scholar 

  86. King, G. W. et al. The XUV environments of exoplanets from Jupiter-size to super-Earth. Mon. Not. R. Astron. Soc. 478, 1193–1208 (2018).

    ADS  CAS  Google Scholar 

  87. Chadney, J. M., Galand, M., Unruh, Y. C., Koskinen, T. T. & Sanz-Forcada, J. XUV-driven mass lossfrom extrasolar giant planets orbiting active stars. Icarus 250, 357–367 (2015).

    ADS  CAS  Google Scholar 

  88. Watson, A. J., Donahue, T. M. & Walker, J. C. G. The dynamics of a rapidly escaping atmosphere: applications to the evolution of Earth and Venus. Icarus 48, 150–166 (1981).

    ADS  CAS  Google Scholar 

  89. Erkaev, N. V. et al. Roche lobe effects on the atmospheric loss from “Hot Jupiters”. Astron. Astrophys. 472, 329–334 (2007).

    ADS  CAS  Google Scholar 

  90. Kubyshkina, D. et al. Grid of upper atmosphere models for 1–40 M planets: application to CoRoT-7b and HD 219134b,c. Astron. Astrophys. 619, A151 (2018).

    CAS  Google Scholar 

  91. Kubyshkina, D. et al. Overcoming the limitations of the energy-limited approximation for planet atmospheric escape. Astrophys. J. Lett. 866, 18 (2018).

    ADS  Google Scholar 

  92. Madhusudhan, N. & Winn, J. N. Empirical constraints on trojan companions and orbital eccentricities in 25 transiting exoplanetary systems. Astrophys. J. 693, 784–793 (2009).

    ADS  Google Scholar 

  93. Ford, E. B. & Gaudi, B. S. Observational constraints on trojans of transiting extrasolar planets. Astrophys. J. Lett. 652, 137–140 (2006).

    ADS  Google Scholar 

  94. Janson, A. Systematic search for trojan planets in the Kepler data. Astrophys. J. 774, 156 (2013).

    ADS  Google Scholar 

  95. Lillo-Box, J. et al. The TROY project: searching for co-orbital bodies to known planets. I. Project goals and first results from archival radial velocity. Astron. Astrophys. 609, A96 (2018).

    Google Scholar 

  96. Lillo-Box, J. et al. The TROY project. II. Multi-technique constraints on exotrojans in nine planetary systems. Astron. Astrophys. 618, A42 (2018).

    Google Scholar 

  97. Lillo-Box, J. et al. Kepler-91b: a planet at the end of its life. Planet and giant host star properties via lightcurve variations. Astron. Astrophys. 562, A109 (2014).

    Google Scholar 

  98. Leleu, A. et al. Co-orbital exoplanets from close period candidates: the TOI-178 case. Astron. Astrophys. 624 A46 (2019).

    Google Scholar 

  99. Laughlin, G. & Chambers, J. E. Extrasolar trojans: the viability and detectability of planets in the 1:1 resonance. Astron. J. 124, 592–600 (2002).

    ADS  Google Scholar 

  100. Leleu, A., Robutel, P., Correia, A. C. M. & Lillo-Box, J. Detection of co-orbital planets by combining transit and radial-velocity measurements. Astron. Astrophys. 599, L7 (2017).

    ADS  Google Scholar 

  101. Foreman-Mackey, D., Hogg, D. W., Lang, D. & Goodman, J. emcee: the MCMC hammer. Publ. Astron. Soc. Pacif. 125, 306–312 (2013).

    ADS  Google Scholar 

  102. Kane, S. R. Worlds without moons: exomoon constraints for compact planetary systems. Astrophys. J. Lett. 839, L19 (2017).

    ADS  Google Scholar 

  103. 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).

    ADS  Google Scholar 

  104. Shakura, N. I. & Sunyaev, R. A. Black holes in binary systems. Observational appearance. Astron. Astrophys. 500, 33–51 (1973).

    ADS  Google Scholar 

  105. Nakamoto, T. & Nakagawa, Y. Formation, early evolution, and gravitational stability of protoplanetary disks. Astrophys. J. 421, 640 (1994).

    ADS  Google Scholar 

  106. Hueso, R. & Guillot, T. Evolution of protoplanetary disks: constraints from DM Tauri and GM Aurigae. Astron. Astrophys. 442, 703–725 (2005).

    ADS  CAS  Google Scholar 

  107. Baraffe, I., Homeier, D., Allard, F. & Chabrier, G. New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit. Astron. Astrophys. 577, A42 (2015).

    ADS  Google Scholar 

  108. Clarke, C. J., Gendrin, A. & Sotomayor, M. The dispersal of circumstellar discs: the role of the ultraviolet switch. Mon. Not. R. Astron. Soc. 328, 485–491 (2001).

    ADS  Google Scholar 

  109. Matsuyama, I., Johnstone, D. & Hartmann, L. Viscous diffusion and photoevaporation of stellar disks. Astrophys. J. 582, 893–904 (2003).

    ADS  Google Scholar 

  110. Ida, S. & Makino, J. Scattering of planetesimals by a protoplanet: slowing down of runaway growth. Icarus 106, 210–227 (1993).

    ADS  Google Scholar 

  111. Ohtsuki, K., Stewart, G. R. & Ida, S. Evolution of planetesimal velocities based on three-body orbital integrations and growth of protoplanets. Icarus 155, 436–453 (2002).

    ADS  Google Scholar 

  112. Thommes, E. W., Duncan, M. J. & Levison, H. F. Oligarchic growth of giant planets. Icarus 161, 431–455 (2003).

    ADS  Google Scholar 

  113. Inaba, S. & Ikoma, M. Enhanced collisional growth of a protoplanet that has an atmosphere. Astron. Astrophys. 410, 711–723 (2003).

    ADS  Google Scholar 

  114. Bodenheimer, P. & Pollack, J. B. Calculations of the accretion and evolution of giant planets: the effects of solid cores. Icarus 67, 391–408 (1986).

    ADS  Google Scholar 

  115. Pollack, J. B. et al. Formation of the giant planets by concurrent accretion of solids and gas. Icarus 124, 62–85 (1996).

    ADS  Google Scholar 

  116. Lee, E. J. & Chiang, E. To cool is to accrete: analytic scalings for nebular accretion of planetary atmospheres. Astrophys. J. 811, 41 (2015).

    ADS  Google Scholar 

  117. Bodenheimer, P., Hubickyj, O. & Lissauer, J. J. Models of the in situ formation of detected extrasolar giant planets. Icarus 143, 2–14 (2000).

    ADS  Google Scholar 

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

    ADS  Google Scholar 

  119. Broeg, C. H. & Benz, W. Giant planet formation: episodic impacts versus gradual core growth. Astron. Astrophys. 538, A90 (2012).

    ADS  MATH  Google Scholar 

  120. Coleman, G. A. L. & Nelson, R. P. On the formation of planetary systems via oligarchic growth in thermally evolving viscous discs. Mon. Not. R. Astron. Soc. 445, 479–499 (2014).

    ADS  Google Scholar 

  121. Paardekooper, S. J., Baruteau, C. & Kley, W. A torque formula for non-isothermal Type I planetary migration - II. Effects of diffusion. Mon. Not. R. Astron. Soc. 410, 293–303 (2011).

    ADS  Google Scholar 

  122. Fendyke, S. M. & Nelson, R. P. On the corotation torque for low-mass eccentric planets. Mon. Not. R. Astron. Soc. 437, 96–107 (2014).

    ADS  Google Scholar 

  123. Dittkrist, K. M., Mordasini, C., Klahr, H., Alibert, Y. & Henning, T. Impacts of planet migration models on planetary populations. Effects of saturation, cooling and stellar irradiation. Astron. Astrophys. 567, A121 (2014).

    Google Scholar 

  124. Jin, S. et al. Planetary population synthesis coupled with atmospheric escape: a statistical view of evaporation. Astrophys. J. 795, 65 (2014).

    ADS  Google Scholar 

  125. Jin, S. & Mordasini, C. Compositional imprints in density-distance-time: a rocky composition for close-in low-mass exoplanets from the location of the valley of evaporation. Astrophys. J. 853, 163 (2018).

    ADS  Google Scholar 

  126. Benítez-Llambay, P., Masset, F. & Beaugé, C. The mass-period distribution of close-in exoplanets. Astron. Astrophys. 528, A2 (2011).

    ADS  Google Scholar 

  127. Mordasini, C., Alibert, Y. & Benz, W. Extrasolar planet population synthesis. I. Method, formation tracks, and mass-distance distribution. Astron. Astrophys. 501, 1139–1160 (2009).

    ADS  Google Scholar 

  128. Tychoniec, L. et al. The VLA Nascent Disk and Multiplicity Survey of Perseus Protostars (VANDAM). IV. Free–free emission from protostars: links to infrared properties, outflow tracers, and protostellar disk masses. Astrophys. J. Suppl. Ser. 238, 19 (2018).

    ADS  Google Scholar 

  129. Andrews, S. M., Wilner, D. J., Hughes, A. M., Qi, C. & Dullemond, C. P. Protoplanetary disk structures in Ophiuchus. II. Extension to fainter sources. Astrophys. J. 723, 1241–1254 (2010).

    ADS  CAS  Google Scholar 

  130. Venuti, L. et al. CSI 2264: investigating rotation and its connection with disk accretion in the young open cluster NGC 2264. Astron. Astrophys. 599, A23 (2017).

    Google Scholar 

  131. Lodders, K. Solar system abundances and condensation temperatures of the elements. Astrophys. J. 591, 1220–1247 (2003).

    ADS  CAS  Google Scholar 

  132. Ansdell, M. et al. ALMA survey of Lupus protoplanetary disks. II. Gas disk radii. Astrophys. J. 859, 21 (2018).

    ADS  Google Scholar 

  133. Ivanov, P. B. & Papaloizou, J. C. B. On the tidal interaction of massive extrasolar planets on highly eccentric orbits. Mon. Not. R. Astron. Soc. 347, 437–453 (2004).

    ADS  Google Scholar 

  134. Vick, M. & Lai, D. Dynamical tides in highly eccentric binaries: chaos, dissipation, and quasi-steady state. Mon. Not. R. Astron. Soc. 476, 482–495 (2018).

    ADS  Google Scholar 

  135. Wu, Y. Diffusive tidal evolution for migrating hot Jupiters. Astron. J. 155, 118 (2018).

    ADS  Google Scholar 

  136. Vick, M., Lai, D. & Anderson, K. R. Chaotic tides in migrating gas giants: forming hot and transient warm Jupiters via Lidov–Kozai migration. Mon. Not. R. Astron. Soc. 484, 5645–5668 (2019).

    ADS  CAS  Google Scholar 

  137. Veras, D. & Fuller, J. Tidal circularization of gaseous planets orbiting white dwarfs. Mon. Not. R. Astron. Soc. 489, 2941–2953 (2019).

    ADS  Google Scholar 

  138. Tinetti, G. et al. A chemical survey of exoplanets with ARIEL. Exp. Astron. 46, 135–209 (2018).

    ADS  Google Scholar 

  139. Stassun, K. G. et al. The revised TESS input catalog and candidate target list. Astron. J. 158, 138 (2019).

    ADS  Google Scholar 

  140. Skrutskie, M. F. et al. The Two Micron All Sky Survey (2MASS). Astron. J. 131, 1163–1183 (2006).

    ADS  Google Scholar 

Download references

Acknowledgements

This paper includes data collected by the TESS missions, which are publicly available from MAST. Funding for the TESS mission is provided by NASA’s Science Mission directorate. We acknowledge the use of public TESS Alert data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This research made use of the Exoplanet Follow-up Observation Program website and the NASA Exoplanet Archive, which are operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This work makes use of observations from the LCOGT network and is based in part on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme IDs 1102.C-0249 and P103.C-0449. Some of the observations presented in the paper used the High-Resolution Imaging instrument Zorro at Gemini South (programme ID GS-2019B-Q-111). Zorro was funded by the NASA Exoplanet Exploration Program and built at the NASA Ames Research Center by S.B.H., N. Scott, E. P. Horch and E. Quigley. D.J.A., D.V. and S.L.C. acknowledge support from the STFC via Ernest Rutherford Fellowships ST/R00384X/1, ST/P003850/1 and ST/R003726/1, respectively. M.B. and S.Gandhi acknowledge support from the STFC research grant ST/S000631/1. G.M.K. is supported by the Royal Society as a Royal Society University Research Fellow. F.M. acknowledges support from a Royal Society Dorothy Hodgkin Fellowship. K.G.S. acknowledges partial support from NASA grant 17-XRP17 2-0024. C.Z. is supported by a Dunlap Fellowship at the Dunlap Institute for Astronomy and Astrophysics, funded through an endowment established by the Dunlap family and the University of Toronto. A.W.M. was supported by NASA grant 80NSSC19K0097 to the University of North Carolina at Chapel Hill. D.J.A.B. acknowledges support from the UK Space Agency. C.X.H. and M.N.G. acknowledge support from the Juan Carlos Torres Fellowship. This work was financed by FEDER (Fundo Europeu de Desenvolvimento Regional) funds through the COMPETE 2020 Operational Programme for Competitiveness and Internationalisation (POCI) and by Portuguese funds through FCT (Fundação para a Ciência e a Tecnologia) in the framework of projects UID/FIS/04434/2019; PTDC/FIS-AST/32113/2017 and POCI-01-0145-FEDER-032113; PTDC/FIS-AST/28953/2017 and POCI-01-0145-FEDER-028953. S.G.S., V.A., S.C.C.B. and O.D.S.D. acknowledge support from FCT through Investigador FCT contracts IF/00028/2014/CP1215/CT0002, IF/00650/2015/CP1273/CT0001, IF/01312/2014/CP1215/CT0004 and DL 57/2016/CP1364/CT0004. S.H. acknowledges support from fellowships PD/BD/128119/2016 funded by FCT (Portugal). Work by J.N.W. was partly funded by the Heising-Simons Foundation. C.A.W. acknowledges support from UK Science Technology and Facility Council grant ST/P000312/1. J.L.-B. and D. Barrado are funded by the Spanish State Research Agency (AEI) Projects ESP2017-87676-C5-1-R and MDM-2017-0737 Unidad de Excelencia María de Maeztu – Centro de Astrobiología (INTA-CSIC). J.S.J. acknowledges funding by Fondecyt through grant 1161218 and partial support from CATA-Basal (PB06, Conicyt). J.I.V. acknowledges support from CONICYT-PFCHA/Doctorado Nacional-21191829, Chile. The French group acknowledges financial support from the French Programme National de Planétologie (PNP, INSU). F.M. acknowledges support from the Royal Society Dorothy Hodgkin Fellowship. C.M. and A.E. acknowledge support from the Swiss National Science Foundation under grant BSSGI0_155816 “PlanetsInTime”. Parts of this work have been carried out within the framework of the NCCR PlanetS supported by the Swiss National Science Foundation.

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Authors and Affiliations

Authors

Contributions

D.J.A. is Principal Investigator of the NCORES HARPS programme, which measured the planet’s mass, and a member of the NGTS consortium; D.J.A. developed much of the text and main figures and coordinated all contributions. T.A.L. performed the joint PASTIS analysis. V.A., S.G.S. and N.C.S. performed stellar spectral analysis including chemical abundances. R.A.B. and F.M. provided text analysing potential formation scenarios. K.A.C. and E.L.N.J. coordinated the TFOP SG1 photometric follow-up of the system. K.I.C. and T.G. performed analysis of the LCOGT photometric follow-up of the system. A.E. and C.M. applied and analysed the Bern Population Synthesis Models. C.X.H. and L.S. developed and ran the MIT Quick Look Pipeline, which identified the candidate in the TESS data. G.W.K. performed the photoevaporation analysis. J.L.-B. obtained and analysed the Astralux data and synthesized all high-resolution imaging results. E.M. obtained the NaCo imaging data. H.O. contributed to the NCORES HARPS programme and the NGTS survey and helped to create the main figures. J.O., O.M., M.D., R.H., M. Lozovsky and C.D. performed the interior-structure calculations. D.V. performed analysis on the potential for tidal self-disruption. C.Z. obtained the SOAR data and provided text summarising the SOAR results. T.-G.T. obtained a further transit with the PEST telescope. J.J.L. contributed to the internal structure discussion. K.G.S. provided the independent check of stellar parameters. M.B. and S. Gandhi calculated estimates of the required telescope time for atmospheric characterization. D.R.A., M.M., E.M.B., C.A.W., J.S.J., J.I.V., J.S.A., D. Bayliss, C. Belardi, M.R.B., S.L.C., A.C., P.E., S. Gill, M.R.G., M.N.G., M. Lendl, J.M., D.P., D.Q., L.R., R.H.T. and R.G.W. contributed to the NGTS facility, in planning, management, data collection or detrending. D.J.A.B., S.H., D. Barrado, S.C.C.B., P.A.W., L.D.N., D. Bayliss, F.B., B.F.C., R.F.D., O.D.S.D., X.D., P.F., J.J., G.M.K., A.S., S.U., P.A.W., J.M.A. and A.O. contributed to the HARPS large programme under which the HARPS data were obtained. D.R.C., I.J.M.C., J.E.S. and S.B.H. contributed to the NaCo imaging data. C. Briceño, N.L. and A.W.M. contributed to the SOAR imaging data. K.D.C., M.F., J.S.J., E.L.N.J., G.R.R., P.R., S.S., E.T., R.V., J.N.W., J.N.V. and Z.Z. provided essential contributions to the TESS mission, which discovered the candidate. All authors read the manuscript and provided general comments.

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Correspondence to David J. Armstrong.

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Extended data figures and tables

Extended Data Fig. 1 Photometric data captured by the LCOGT network.

a, b, Data captured on the nights of 30 July 2019 ut (a) and 9 August 2019 ut (b). The best-fitting model is plotted in red and the binned data in orange. Error bars of individual points show one standard deviation. In the case of binned measurements, points and error bars show the weighted mean and its standard error, respectively.

Extended Data Fig. 2 HARPS activity correlation indicators.

a, HARPS radial velocities plotted against their bisector value. Colours represent the time of observation measured in BJD–2,400,000. b, As for a, for the FWHM of the CCF. No correlation is seen in either case. All error bars show one standard deviation.

Extended Data Fig. 3 Tests on the HARPS residuals.

a, CCF for the HARPS spectra computed using a G2V template. A Gaussian fit has been removed to leave the residual noise. No clear evidence of a contaminating star is seen. b, Periodogram of the HARPS RV residuals. No evidence of periodic structure is found. FAP represents false-alarm probability.

Extended Data Fig. 4 Collected high-resolution imaging results from AstraLux/CAHA, NaCo/VLT, HRCam/SOAR and Zorro/Gemini (562 nm).

ac, Images from AstraLux (a), NaCo (b) and HRCam (c). d, Sensitivity curves for ac and the Zorro 562-nm observation. Our simultaneous 832-nm Zorro observation provides a similar result. The 1% and 10% contrast curves are also plotted.

Extended Data Fig. 5 TOI-849 compared to field stars.

Abundance ratio [X/Fe] against stellar metallicity for TOI-849 (black) and for field stars from the HARPS sample (grey) with similar stellar parameters: Teff = 5,329 ± 200 K, logg = 4.28 ± 0.20 dex and [Fe/H] = +0.20 ± 0.20 dex. All error bars show one standard deviation.

Extended Data Fig. 6 Planet mass against time for three similar planets to TOI-849b in the Bern Population Synthesis models.

Grey shaded regions mark the parameters of TOI-849b. Stars mark the time of a giant impact. The inset shows the envelope mass, which is removed after collision.

Extended Data Table 1 List of stellar and planetary parameters used in the analysis
Extended Data Table 2 List of instrument parameters used in the analysis
Extended Data Table 3 Stellar properties of TOI-849
Extended Data Table 4 HARPS radial velocities

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Armstrong, D.J., Lopez, T.A., Adibekyan, V. et al. A remnant planetary core in the hot-Neptune desert. Nature 583, 39–42 (2020). https://doi.org/10.1038/s41586-020-2421-7

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