A Neptune-sized transiting planet closely orbiting a 5–10-million-year-old star

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Abstract

Theories of the formation and early evolution of planetary systems postulate that planets are born in circumstellar disks, and undergo radial migration during and after dissipation of the dust and gas disk from which they formed1,2. The precise ages of meteorites indicate that planetesimals—the building blocks of planets—are produced within the first million years of a star’s life3. Fully formed planets are frequently detected on short orbital periods around mature stars. Some theories suggest that the in situ formation of planets close to their host stars is unlikely and that the existence of such planets is therefore evidence of large-scale migration4,5. Other theories posit that planet assembly at small orbital separations may be common6,7,8. Here we report a newly born, transiting planet orbiting its star with a period of 5.4 days. The planet is 50 per cent larger than Neptune, and its mass is less than 3.6 times that of Jupiter (at 99.7 per cent confidence), with a true mass likely to be similar to that of Neptune. The star is 5–10 million years old and has a tenuous dust disk extending outward from about twice the Earth–Sun separation, in addition to the fully formed planet located at less than one-twentieth of the Earth–Sun separation.

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Figure 1: Light curve of K2-33.
Figure 2: Constraints on astrophysical false-positive scenarios.

References

  1. 1

    Kuiper, G. P. On the origin of the Solar System. Proc. Natl Acad. Sci. USA 37, 1–14 (1951)

    Article  ADS  CAS  PubMed  Google Scholar 

  2. 2

    Kley, W. & Nelson, R. P. Planet-disk interaction and orbital evolution. Annu. Rev. Astron. Astrophys. 50, 211–249 (2012)

    Article  ADS  Google Scholar 

  3. 3

    Connelly, J. N. et al. The absolute chronology and thermal processing of solids in the solar protoplanetary disk. Science 338, 651–655 (2012)

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  4. 4

    Lin, D. N. C., Bodenheimer, P. & Richardson, D. C. Orbital migration of the planetary companion of 51 Pegasi to its present location. Nature 380, 606–607 (1996)

    Article  ADS  CAS  Google Scholar 

  5. 5

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

    Article  ADS  Google Scholar 

  6. 6

    Hansen, B. M. S. & Murray, N. Migration then assembly: formation of Neptune-mass planets inside 1 AU. Astrophys. J. 751, 158 (2012)

    Article  ADS  Google Scholar 

  7. 7

    Chatterjee, S. & Tan, J. C. Inside-out planet formation. Astrophys. J. 780, 53 (2014)

    Article  ADS  Google Scholar 

  8. 8

    Boley, A. C., Granados Contreras, A. P. & Gladman, B. The in situ formation of giant planets at short orbital periods. Astrophys. J. 817, L17 (2016)

    Article  ADS  CAS  Google Scholar 

  9. 9

    Vanderburg, A. et al. Planetary candidates from the first year of the K2 mission. Astrophys. J. Suppl. Ser. 222, 14 (2016)

    Article  ADS  Google Scholar 

  10. 10

    Crossfield, I. J. M. et al. A nearby M star with three transiting super-Earths discovered by K2. Astrophys. J. 804, 10 (2015)

    Article  ADS  Google Scholar 

  11. 11

    Preibisch, T., Guenther, E. & Zinnecker, H. A large spectroscopic survey for young low-mass members of the Upper Scorpius OB association. Astron. J. 121, 1040–1049 (2001)

    Article  ADS  Google Scholar 

  12. 12

    Preibisch, T., Brown, A. G. A., Bridges, T., Guenther, E. & Zinnecker, H. Exploring the full stellar population of the Upper Scorpius OB association. Astron. J. 124, 404–416 (2002)

    Article  ADS  Google Scholar 

  13. 13

    Luhman, K. L. & Mamajek, E. E. The disk population of the Upper Scorpius association. Astrophys. J. 758, 31 (2012)

    Article  ADS  Google Scholar 

  14. 14

    McQuillan, A., Aigrain, S. & Mazeh, T. Measuring the rotation period distribution of field M dwarfs with Kepler. Mon. Not. R. Astron. Soc. 432, 1203–1216 (2013)

    Article  ADS  Google Scholar 

  15. 15

    Kurosawa, R., Harries, T. J. & Littlefair, S. P. Radial and rotational velocities of young brown dwarfs and very low-mass stars in the Upper Scorpius OB association and the ρ Ophiuchi cloud core. Mon. Not. R. Astron. Soc. 372, 1879–1887 (2006)

    Article  ADS  Google Scholar 

  16. 16

    Bouy, H. & Martín, E. L. Proper motions of cool and ultracool candidate members in the Upper Scorpius OB association. Astron. Astrophys. 504, 981–990 (2009)

    Article  ADS  CAS  Google Scholar 

  17. 17

    Herczeg, G. J. & Hillenbrand, L. A. Empirical isochrones for low mass stars in nearby young associations. Astrophys. J. 808, 23 (2015)

    Article  ADS  CAS  Google Scholar 

  18. 18

    Pecaut, M. J. & Mamajek, E. E. Intrinsic colors, temperatures, and bolometric corrections of pre-main-sequence stars. Astrophys. J. Suppl. Ser. 208, 9 (2013)

    Article  ADS  CAS  Google Scholar 

  19. 19

    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)

    Article  ADS  CAS  Google Scholar 

  20. 20

    Kraus, A. L. & Hillenbrand, L. A. The role of mass and environment in multiple-star formation: a 2MASS survey of wide multiplicity in three young associations. Astrophys. J. 662, 413–430 (2007)

    Article  ADS  CAS  Google Scholar 

  21. 21

    Armitage, P. J. Dynamics of protoplanetary disks. Annu. Rev. Astron. Astrophys. 49, 195–236 (2011)

    Article  ADS  CAS  Google Scholar 

  22. 22

    Bowler, B. P., Liu, M. C., Shkolnik, E. L. & Tamura, M. Planets around low-mass stars (PALMS). IV. The outer architecture of M dwarf planetary systems. Astrophys. J. Suppl. Ser. 216, 7 (2014)

    Article  ADS  Google Scholar 

  23. 23

    Morton, T. D. VESPA: false positive probabilities calculator. Astrophys. Source Code Library ascl :1503.011, http://ascl.net/1503.011 (2015)

  24. 24

    Carpenter, J. M., Mamajek, E. E., Hillenbrand, L. A. & Meyer, M. R. Debris disks in the Upper Scorpius OB association. Astrophys. J. 705, 1646–1671 (2009)

    Article  ADS  Google Scholar 

  25. 25

    Carpenter, J. M., Mamajek, E. E., Hillenbrand, L. A. & Meyer, M. R. Evidence for mass-dependent circumstellar disk evolution in the 5 Myr old Upper Scorpius OB association. Astrophys. J. 651, L49–L52 (2006)

    Article  ADS  CAS  Google Scholar 

  26. 26

    Trilling, D. E. et al. Debris disks around Sun-like stars. Astrophys. J. 674, 1086–1105 (2008)

    Article  ADS  CAS  Google Scholar 

  27. 27

    Barenfeld, S., Carpenter, J. M., Ricci, L. & Isella, A. ALMA observations of circumstellar disks in the Upper Scorpius OB association. Astrophys. J. (in the press); preprint at https://arxiv.org/abs/1605.05772.

  28. 28

    Dressing, C. D. & Charbonneau, D. The occurrence rate of small planets around small stars. Astrophys. J. 767, 95 (2013)

    Article  ADS  Google Scholar 

  29. 29

    Dressing, C. D. & Charbonneau, D. The occurrence of potentially habitable planets orbiting M dwarfs estimated from the full Kepler dataset and an empirical measurement of the detection sensitivity. Astrophys. J. 807, 45 (2015)

    Article  ADS  CAS  Google Scholar 

  30. 30

    de Zeeuw, P. T., Hoogerwerf, R., de Bruijne, J. H. J., Brown, A. G. A. & Blaauw, A. A HIPPARCOS census of the nearby OB associations. Astron. J. 117, 354–399 (1999)

    Article  ADS  Google Scholar 

  31. 31

    Lépine, S. & Simon, M. Nearby young stars selected by proper motion. I. Four new members of the β Pictoris moving group from the Tycho-2 catalog. Astron. J. 137, 3632–3645 (2009)

    Article  ADS  CAS  Google Scholar 

  32. 32

    Chen, C. H. et al. A Magellan MIKE and Spitzer MIPS study of 1.5-1.0M stars in Scorpius-Centaurus. Astrophys. J. 738, 122 (2011)

    Article  ADS  Google Scholar 

  33. 33

    de Bruijne, J. H. J. Structure and colour-magnitude diagrams of Scorpius OB2 based on kinematic modelling of Hipparcos data. Mon. Not. R. Astron. Soc. 310, 585–617 (1999)

    Article  ADS  Google Scholar 

  34. 34

    Seager, S. & Mallén-Ornelas, G. A unique solution of planet and star parameters from an extrasolar planet transit light curve. Astrophys. J. 585, 1038–1055 (2003)

    Article  ADS  Google Scholar 

  35. 35

    Lomb, N. R. Least-squares frequency analysis of unequally spaced data. Astrophys. Space Sci. 39, 447–462 (1976)

    Article  ADS  Google Scholar 

  36. 36

    Scargle, J. D. Studies in astronomical time series analysis. II—Statistical aspects of spectral analysis of unevenly spaced data. Astrophys. J. 263, 835–853 (1982)

    Article  ADS  Google Scholar 

  37. 37

    Howell, S. B. et al. The K2 mission: characterization and early results. Publ. Astron. Soc. Pacif. 126, 398–408 (2014)

    Article  ADS  Google Scholar 

  38. 38

    David, T. J., Hillenbrand, L. A., Cody, A. M., Carpenter, J. M. & Howard, A. W. K2 discovery of young eclipsing binaries in Upper Scorpius: direct mass and radius determinations for the lowest mass stars and initial characterization of an eclipsing brown dwarf binary. Astrophys. J. 816, 21 (2015)

    Article  ADS  Google Scholar 

  39. 39

    Kreidberg, L. BATMAN: BAsic Transit Model cAlculatioN in Python. Publ. Astron. Soc. Pacif. 127, 1161–1165 (2015)

    Article  ADS  Google Scholar 

  40. 40

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

    Article  ADS  Google Scholar 

  41. 41

    Claret, A., Hauschildt, P. H. & Witte, S. New limb-darkening coefficients for PHOENIX/1D model atmospheres. I. Calculations for 1500 K ≤ Teff ≤ 4800 K Kepler, CoRot, Spitzer, uvby, UBVRIJHK, Sloan, and 2MASS photometric systems. Astron. Astrophys. 546, A14 (2012)

    Article  ADS  Google Scholar 

  42. 42

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

    Article  ADS  Google Scholar 

  43. 43

    Jackson, R. J. & Jeffries, R. D. The effect of starspots on the radii of low-mass pre-main-sequence stars. Mon. Not. R. Astron. Soc. 441, 2111–2123 (2014)

    Article  ADS  Google Scholar 

  44. 44

    Petigura, E. A. et al. Two transiting Earth-size planets near resonance orbiting a nearby cool star. Astrophys. J. 811, 102 (2015)

    Article  ADS  CAS  Google Scholar 

  45. 45

    Vogt, S. S. et al. in Instrumentation in Astronomy VIII (eds Crawford, D. L. & Craine, E. R. ) Proceedings of SPIE Vol. 2198, 362–375, http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=959834 (SPIE, 1994)

  46. 46

    Nidever, D. L., Marcy, G. W., Butler, R. P., Fischer, D. A. & Vogt, S. S. Radial velocities for 889 late-type stars. Astrophys. J. Suppl. Ser. 141, 503–522 (2002)

    Article  ADS  Google Scholar 

  47. 47

    Montet, B. T., Crepp, J. R., Johnson, J. A., Howard, A. W. & Marcy, G. W. The TRENDS high-contrast imaging survey. IV. The occurrence rate of giant planets around M dwarfs. Astrophys. J. 781, 28 (2014)

    Article  ADS  Google Scholar 

  48. 48

    Kolbl, R., Marcy, G. W., Isaacson, H. & Howard, A. W. Detection of stars within ~0.8″ of Kepler objects of interest. Astron. J. 149, 18 (2014)

    Article  ADS  Google Scholar 

  49. 49

    Tuthill, P. G., Monnier, J. D., Danchi, W. C., Wishnow, E. H. & Haniff, C. A. Michelson interferometry with the Keck I telescope. Publ. Astron. Soc. Pacif. 112, 555–565 (2000)

    Article  ADS  Google Scholar 

  50. 50

    Baldwin, J. E., Haniff, C. A., Mackay, C. D. & Warner, P. J. Closure phase in high-resolution optical imaging. Nature 320, 595–597 (1986)

    Article  ADS  Google Scholar 

  51. 51

    Readhead, A. C. S. et al. Diffraction-limited imaging with ground-based optical telescopes. Astron. J. 95, 1278–1296 (1988)

    Article  ADS  Google Scholar 

  52. 52

    Kraus, A. L., Ireland, M. J., Martinache, F. & Hillenbrand, L. A. Mapping the shores of the brown dwarf desert. II. Multiple star formation in Taurus-Auriga. Astrophys. J. 731, 8 (2011)

    Article  ADS  Google Scholar 

  53. 53

    Hinkley, S. et al. Discovery of seven companions to intermediate-mass stars with extreme mass ratios in the Scorpius-Centaurus association. Astrophys. J. 806, L9 (2015)

    Article  ADS  Google Scholar 

  54. 54

    Kraus, A. L. & Hillenbrand, L. A. Multiple star formation to the bottom of the initial mass function. Astrophys. J. 757, 141 (2012)

    Article  ADS  Google Scholar 

  55. 55

    Howell, S. B. et al. Kepler-21b: a 1.6 REarth planet transiting the bright oscillating F subgiant star HD 179070. Astrophys. J. 746, 123 (2012)

    Article  ADS  Google Scholar 

  56. 56

    Girardi, L., Groenewegen, M. A. T., Hatziminaoglou, E. & da Costa, L. Star counts in the Galaxy. Simulating from very deep to very shallow photometric surveys with the TRILEGAL code. Astron. Astrophys. 436, 895–915 (2005)

    Article  ADS  Google Scholar 

  57. 57

    Girardi, L. et al. TRILEGAL, a TRIdimensional modeL of thE GALaxy: status and future. Astrophys. Space Sci. Proc. 26, 165–170 (2012)

    Article  ADS  Google Scholar 

  58. 58

    Dieterich, S. B., Henry, T. J., Golimowski, D. A., Krist, J. E. & Tanner, A. M. The solar neighborhood. XXVIII. The multiplicity fraction of nearby stars from 5 to 70 AU and the brown dwarf desert around M dwarfs. Astron. J. 144, 64 (2012)

    Article  ADS  Google Scholar 

  59. 59

    Preibisch, T. & Mamajek, E. The Nearest OB Association: Scorpius-Centaurus (Sco OB2) (ed. Reipurth, B. ) 235–284, http://aspmonographs.org/custom/publications/paper/005-0235.html (Astronomical Society of the Pacific Monograph Publications, 2008)

  60. 60

    Blaauw, A. in NATO Advanced Science Institutes Series C (eds, Lada, C. J. & Kylafis, N. D. ) Vol. 342, 125–154 (ASI, 1991)

  61. 61

    de Zeeuw, T. & Brand, J. in Birth and Evolution of Massive Stars and Stellar Groups (eds Boland, W. & van Woerden, H. ) Astrophysics and Space Science Library Vol. 120, 95–101 (Springer, 1985)

  62. 62

    de Geus, E. J., de Zeeuw, P. T. & Lub, J. Physical parameters of stars in the Scorpio-Centaurus OB association. Astron. Astrophys. 216, 44–61 (1989)

    ADS  Google Scholar 

  63. 63

    Preibisch, T. & Zinnecker, H. The history of low-mass star formation in the Upper Scorpius OB association. Astron. J. 117, 2381–2397 (1999)

    Article  ADS  Google Scholar 

  64. 64

    Slesnick, C. L., Hillenbrand, L. A. & Carpenter, J. M. A large-area search for low-mass objects in Upper Scorpius. II. Age and mass distributions. Astrophys. J. 688, 377–397 (2008)

    Article  ADS  CAS  Google Scholar 

  65. 65

    Lodieu, N., Dobbie, P. D. & Hambly, N. C. Multi-fibre optical spectroscopy of low-mass stars and brown dwarfs in Upper Scorpius. Astron. Astrophys. 527, A24 (2011)

    Article  ADS  CAS  Google Scholar 

  66. 66

    Allen, P. R., Trilling, D. E., Koerner, D. W. & Reid, I. N. Luminosity functions of young clusters: modeling the substellar mass regime. Astrophys. J. 595, 1222–1230 (2003)

    Article  ADS  Google Scholar 

  67. 67

    Martín, E. L. Weak and post-T Tauri stars around B-type members of the Scorpius-Centaurus OB association. Astron. J. 115, 351–357 (1998)

    Article  ADS  Google Scholar 

  68. 68

    Frink, S. Kinematics of T Tauri Stars in Nearby Star Forming Regions. PhD thesis, Astronomisches Rechen-Institut Heidelberg (1999); http://adsabs.harvard.edu/abs/1999PhDT.........9F

  69. 69

    Pecaut, M. J., Mamajek, E. E. & Bubar, E. J. A revised age for Upper Scorpius and the star formation history among the F-type members of the Scorpius-Centaurus OB association. Astrophys. J. 746, 154 (2012)

    Article  ADS  Google Scholar 

  70. 70

    Kraus, A. L. et al. The mass-radius relation of young stars. I. USco 5, an M4.5 eclipsing binary in Upper Scorpius observed by K2. Astrophys. J. 807, 3 (2015)

    Article  ADS  CAS  Google Scholar 

  71. 71

    Lodieu, N. et al. An eclipsing double-line spectroscopic binary at the stellar/substellar boundary in the Upper Scorpius OB association. Astron. Astrophys. 584, A128 (2015)

    Article  CAS  Google Scholar 

  72. 72

    Wyatt, M. C. Evolution of debris disks. Annu. Rev. Astron. Astrophys. 46, 339–383 (2008)

    Article  ADS  Google Scholar 

  73. 73

    Mann, A. W. et al. Zodiacal exoplanets in time (ZEIT). I. A Neptune-sized planet orbiting an M4.5 dwarf in the Hyades Star Cluster. Astrophys. J. 818, 46 (2016)

    Article  ADS  Google Scholar 

  74. 74

    David, T. J. et al. New Pleiades eclipsing binaries and a Hyades transiting system identified by K2. Astron. J. 151, 112 (2016)

    Article  ADS  Google Scholar 

  75. 75

    Quinn, S. N. et al. Two “b”s in the beehive: the discovery of the first hot Jupiters in an open cluster. Astrophys. J. 756, L33 (2012)

    Article  ADS  CAS  Google Scholar 

  76. 76

    Malavolta, L. et al. The GAPS programme with HARPS-N at TNG. XI. Pr 0211 in M 44: the first multi-planet system in an open cluster. Astron. Astrophys. 588, A118 (2016)

    Article  CAS  Google Scholar 

  77. 77

    Rucinski, S. M. et al. Photometric variability of the T Tauri star TW Hya on time-scales of hours to years. Mon. Not. R. Astron. Soc. 391, 1913–1924 (2008)

    Article  ADS  Google Scholar 

  78. 78

    Huélamo, N. et al. TW Hydrae: evidence of stellar spots instead of a hot Jupiter. Astron. Astrophys. 489, L9–L13 (2008)

    Article  ADS  CAS  Google Scholar 

  79. 79

    Yu, L. et al. Tests of the planetary hypothesis for PTFO 8-8695b. Astrophys. J. 812, 48 (2015)

    Article  ADS  CAS  Google Scholar 

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Acknowledgements

We thank S. Metchev, K. Batygin, B. Benneke, K. Deck, J. Fuller and A. Shporer for discussions, M. Ireland for software used in the aperture masking analysis, and A. Kraus for contributing to the 2011 Keck/NIRC2 data acquisition. T.J.D. is supported by an NSF Graduate Research Fellowship under Grant DGE1144469. E.A.P. is supported through a Hubble Fellowship. I.J.M.C. is supported through a Sagan Fellowship. A.W.H. acknowledges funding from NASA grant NNX16AE75G and NASA Research Support Agreement 1541779. This paper includes data collected by the Kepler mission, funded by the NASA Science Mission directorate. Some data presented here were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and NASA. We acknowledge the important cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community and we are fortunate to be able to conduct observations from this mountain.

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Authors

Contributions

T.J.D. noted the object as a young star, prepared the light curve, validated the transit, and led the overall analysis and the writing of the paper. L.A.H. analysed the 2015 and 2016 Keck/HIRES spectra, participated in team organization, performed general analysis, and contributed substantially to the writing of the paper. E.A.P. analysed raw K2 photometry and validated the transit, provided general guidance on exoplanets and false positives, and contributed substantially to the writing of the paper. J.M.C. was involved in the K2 proposal that included the object, and was principal investigator on the 2011 Keck/NIRC2, 2015 Keck/HIRES, and ALMA observations of the object. I.J.M.C. led the transit fitting and VESPA analysis. A.M.C. analysed the raw K2 photometry and validated the transit. A.W.H. and H.T.I. obtained, reduced, and analysed the 2016 Keck/HIRES spectra. D.R.C. led the clear aperture adaptive optics contrast curve analysis for the 2016 and 2011 data. C.A.B. wrote the proposal for 2016 Keck/NIRC2 follow-up of K2 sources and participated in the observations of the object. S.H. analysed the Keck/NIRC2 aperture masking data and assessed the temperature of the circumstellar dust. J.E.S. provided a rotational velocity analysis and calculated the kinematic distance. S.A.B. took the 2015 Keck/HIRES spectrum and analysed the ALMA data (referred to, but published separately in ref. 27).

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Correspondence to Trevor J. David.

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Nature thanks A. Collier Cameron and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Extended data figures and tables

Extended Data Figure 1 K2 light curve for K2-33 phased on the stellar rotation period of 6.3 days.

Semi-sinusoidal brightness variations due to rotational modulation of starspots. Point colour indicates the relative time of observation, with grey corresponding to earlier in the campaign and dark blue corresponding to later times. Brightness is lowest when the most heavily spotted hemisphere of the stellar surface is along the line of sight. The shape and evolution of the variability pattern depends on the number, geometry, distribution, and lifetime of spots, along with any latitudinal gradient in the rotational speed (differential rotation). The transits of K2-33 b are visible by eye in this figure and are too narrow in rotational phase to be attributed to any feature on or near the stellar surface.

Extended Data Figure 2 Model-dependent age of K2-33.

a, Solid lines show mean stellar density as a function of effective temperature for pre-main-sequence stars having different ages, according to theoretical models19. Grey points represent plausible combinations of density and temperature for K2-33 as determined by light-curve fits and stellar spectroscopy. b, Distribution of implied stellar age based on temperature, density, and pre-main-sequence models. The implied age of 2–7 Myr is consistent with the age we adopted of 5–10 Myr, derived independently. Dark- and light-grey shaded regions indicate 68% and 95% confidence intervals, respectively.

Extended Data Figure 3 Apparent radial velocity variations of K2-33.

Line-of-sight velocities and 1σ uncertainties (standard deviations, indicated by error bars) with respect to the Solar System barycentre from Keck/HIRES are indicated. Radial velocities are mean-subtracted, and the abscissa shows the orbital phase of K2-33 b measured from K2 photometry (mid-transit occurs at zero orbital phase). We rule out radial velocity variations larger than 300 m s−1 at 68.3% confidence, corresponding to a 1.2MJup planet mass. Curves show the expected radial velocity variations for planets having circular orbits and different masses Mp. Radial velocities due to a 1.0MJup planet (blue) are consistent with our observations, while a 4.0MJup planet (red) is ruled out at high confidence.

Extended Data Figure 4 Images of K2-33.

a, K2 target pixel file. b, Sloan Digital Sky Survey (SDSS) optical image. c, Keck/NIRC2 K-band image. Extents of the K2 target pixel file, K2 photometric aperture, and NIRC2 image are shown respectively with black, green, and purple boundaries. In each image, north is up and east is left. Three other sources identified by SDSS reside within the K2 photometric aperture, one of which is a galaxy. All are 7.3–10.1 magnitudes fainter than K2-33 in the SDSS r-filter and below the detection limit of the NIRC2 images, and are thus too faint to produce the observed transits.

Extended Data Figure 5 Sensitivity to non-comoving sources in the vicinity of K2-33.

The blue X marks the star’s position in 2011. Between 2011 and 2016, the star moved by 0.1228″ ± 0.0085″ (red X) owing to proper motion. Contours show the K-band sensitivity to non-comoving stars from adaptive optics imaging from both epochs. The 2011 data set included non-redundant aperture masking, and provided tighter constraints. The combined sensitivity to non-comoving objects is the maximum contrast achieved for either data set. Owing to stellar proper motion, we achieved K-band contrasts of >3.3 mag throughout the ΔRA–Δdec. plane, even at the 2011 and 2016 positions of K2-33.

Extended Data Table 1 Keck/HIRES radial velocities for K2-33

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David, T., Hillenbrand, L., Petigura, E. et al. A Neptune-sized transiting planet closely orbiting a 5–10-million-year-old star. Nature 534, 658–661 (2016). https://doi.org/10.1038/nature18293

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