Below One Earth: The Detection, Formation, and Properties of Subterrestrial Worlds

Abstract

The Solar System includes two planets—Mercury and Mars—significantly less massive than Earth, and all evidence indicates that planets of similar size orbit many stars. In fact, one of the first exoplanets to be discovered is a lunar-mass planet around a millisecond pulsar. Novel classes of exoplanets have inspired new ideas about planet formation and evolution, and these “sub-Earths” should be no exception: they include planets with masses between Mars and Venus for which there are no Solar System analogs. Advances in astronomical instrumentation and recent space missions have opened the sub-Earth frontier for exploration: the Kepler mission has discovered dozens of confirmed or candidate sub-Earths transiting their host stars. It can detect Mars-size planets around its smallest stellar targets, as well as exomoons of comparable size. Although the application of the Doppler method is currently limited by instrument stability, future spectrographs may detect equivalent planets orbiting close to nearby bright stars. Future space-based microlensing missions should be able to probe the sub-Earth population on much wider orbits. A census of sub-Earths will complete the reconnaissance of the exoplanet mass spectrum and test predictions of planet formation models, including whether low-mass M dwarf stars preferentially host the smallest planets. The properties of sub-Earths may reflect their low gravity, diverse origins, and environment, but they will be elusive: Observations of eclipsing systems by the James Webb Space Telescope may give us our first clues to the properties of these small worlds.

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

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7

Notes

  1. 1.

    We discuss large satellites of exoplanets, or “exomoons” in Sect. 4.3.

  2. 2.

    The extended mission has been terminated due to the failure of a second reaction wheel on the spacecraft.

  3. 3.

    http://www.stsci.edu/jwst/science/sensitivity/jwst-phot.

  4. 4.

    Cameron (1985) and Fegley and Cameron (1987) proposed that the mantle of Mercury was evaporated, but this is inconsistent with the MESSENGER estimate of volatile radioactive potassium in the Mercurian crust (Peplowski et al. 2011).

References

  1. C.B. Agnor, D.P. Hamilton, Neptune’s capture of its moon Triton in a binary-planet gravitational encounter. Nature 441, 192–194 (2006). doi:10.1038/nature04792

    ADS  Google Scholar 

  2. E. Agol, J. Steffen, R. Sari, W. Clarkson, On detecting terrestrial planets with timing of giant planet transits. Mon. Not. R. Astron. Soc. 359, 567–579 (2005). doi:10.1111/j.1365-2966.2005.08922.x

    ADS  Google Scholar 

  3. T.J. Ahrens, Impact erosion of terrestrial planetary atmospheres. Annu. Rev. Earth Planet. Sci. 21, 525–555 (1993). doi:10.1146/annurev.ea.21.050193.002521

    ADS  Google Scholar 

  4. S.M. Andrews, K.A. Rosenfeld, A.L. Kraus, D.J. Wilner, The mass dependence between protoplanetary disks and their stellar hosts. Astrophys. J. 771, 129 (2013). doi:10.1088/0004-637X/771/2/129

    ADS  Google Scholar 

  5. M. Bailes, S.D. Bates, V. Bhalerao, N.D.R. Bhat, M. Burgay, S. Burke-Spolaor, N. D’Amico, S. Johnston, M.J. Keith, M. Kramer, S.R. Kulkarni, L. Levin, A.G. Lyne, S. Milia, A. Possenti, L. Spitler, B. Stappers, W. van Straten, Transformation of a star into a planet in a millisecond pulsar binary. Science 333, 1717 (2011). doi:10.1126/science.1208890

    ADS  Google Scholar 

  6. T. Barclay, J.F. Rowe, J.J. Lissauer, D. Huber, F. Fressin, S.B. Howell, S.T. Bryson, W.J. Chaplin, J.-M. Désert, E.D. Lopez, G.W. Marcy, F. Mullally, D. Ragozzine, G. Torres, E.R. Adams, E. Agol, D. Barrado, S. Basu, T.R. Bedding, L.A. Buchhave, D. Charbonneau, J.L. Christiansen, J. Christensen-Dalsgaard, D. Ciardi, W.D. Cochran, A.K. Dupree, Y. Elsworth, M. Everett, D.A. Fischer, E.B. Ford, J.J. Fortney, J.C. Geary, M.R. Haas, R. Handberg, S. Hekker, C.E. Henze, E. Horch, A.W. Howard, R.C. Hunter, H. Isaacson, J.M. Jenkins, C. Karoff, S.D. Kawaler, H. Kjeldsen, T.C. Klaus, D.W. Latham, J. Li, J. Lillo-Box, M.N. Lund, M. Lundkvist, T.S. Metcalfe, A. Miglio, R.L. Morris, E.V. Quintana, D. Stello, J.C. Smith, M. Still, S.E. Thompson, A sub-Mercury-sized exoplanet. Nature 494, 452–454 (2013). doi:10.1038/nature11914

    ADS  Google Scholar 

  7. R. Barry, J. Kruk, J. Anderson, J.-P. Beaulieu, D.P. Bennett, J. Catanzarite, E. Cheng, S. Gaudi, N. Gehrels, S. Kane, J. Lunine, T. Sumi, A. Tanner, W. Traub, The exoplanet microlensing survey by the proposed WFIRST observatory, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol. 8151 (2011). doi:10.1117/12.898574

    Google Scholar 

  8. N.M. Batalha, J.F. Rowe, S.T. Bryson, T. Barclay, C.J. Burke, D.A. Caldwell, J.L. Christiansen, F. Mullally, S.E. Thompson, T.M. Brown, A.K. Dupree, D.C. Fabrycky, E.B. Ford, J.J. Fortney, R.L. Gilliland, H. Isaacson, D.W. Latham, G.W. Marcy, S.N. Quinn, D. Ragozzine, A. Shporer, W.J. Borucki, D.R. Ciardi, T.N. Gautier III, M.R. Haas, J.M. Jenkins, D.G. Koch, J.J. Lissauer, W. Rapin, G.S. Basri, A.P. Boss, L.A. Buchhave, J.A. Carter, D. Charbonneau, J. Christensen-Dalsgaard, B.D. Clarke, W.D. Cochran, B. Demory, J. Desert, E. Devore, L.R. Doyle, G.A. Esquerdo, M. Everett, F. Fressin, J.C. Geary, F.R. Girouard, A. Gould, J.R. Hall, M.J. Holman, A.W. Howard, S.B. Howell, K.A. Ibrahim, K. Kinemuchi, H. Kjeldsen, T.C. Klaus, J. Li, P.W. Lucas, S. Meibom, R.L. Morris, A. Prša, E. Quintana, D.T. Sanderfer, D. Sasselov, S.E. Seader, J.C. Smith, J.H. Steffen, M. Still, M.C. Stumpe, J.C. Tarter, P. Tenenbaum, G. Torres, J.D. Twicken, K. Uddin, J. Van Cleve, L. Walkowicz, W.F. Welsh, Planetary candidates observed by Kepler. III. Analysis of the first 16 months of data. Astrophys. J. Suppl. Ser. 204, 24 (2013). doi:10.1088/0067-0049/204/2/24

    ADS  Google Scholar 

  9. J.L. Bean, A. Seifahrt, H. Hartman, H. Nilsson, G. Wiedemann, A. Reiners, S. Dreizler, T.J. Henry, The CRIRES search for planets around the lowest-mass stars. I. High-precision near-infrared radial velocities with an ammonia gas cell. Astrophys. J. 713, 410–422 (2010). doi:10.1088/0004-637X/713/1/410

    ADS  Google Scholar 

  10. D.P. Bennett, in Detection of Extrasolar Planets by Gravitational Microlensing, ed. by J.W. Mason (Praxis Publishing, Athens, 2008), p. 47. doi:10.1007/978-3-540-74008-7-3

    Google Scholar 

  11. D.P. Bennett, S.H. Rhie, Detecting Earth-mass planets with gravitational microlensing. Astrophys. J. 472, 660 (1996). doi:10.1086/178096

    ADS  Google Scholar 

  12. D.P. Bennett, S.H. Rhie, Simulation of a space-based microlensing survey for terrestrial extrasolar planets. Astrophys. J. 574, 985–1003 (2002). doi:10.1086/340977

    ADS  Google Scholar 

  13. W. Benz, W.L. Slattery, A.G.W. Cameron, Collisional stripping of Mercury’s mantle. Icarus 74, 516–528 (1988). doi:10.1016/0019-1035(88)90118-2

    ADS  Google Scholar 

  14. W. Benz, A. Anic, J. Horner, J.A. Whitby, The origin of Mercury. Space Sci. Rev. 132, 189–202 (2007). doi:10.1007/s11214-007-9284-1

    ADS  Google Scholar 

  15. J. Blum, G. Wurm, Experiments on sticking, restructuring, and fragmentation of preplanetary dust aggregates. Icarus 143, 138–146 (2000). doi:10.1006/icar.1999.6234

    ADS  Google Scholar 

  16. W.J. Borucki, D. Koch, G. Basri, N. Batalha, T. Brown, D. Caldwell, J. Caldwell, J. Christensen-Dalsgaard, W.D. Cochran, E. DeVore, E.W. Dunham, A.K. Dupree, T.N. Gautier, J.C. Geary, R. Gilliland, A. Gould, S.B. Howell, J.M. Jenkins, Y. Kondo, D.W. Latham, G.W. Marcy, S. Meibom, H. Kjeldsen, J.J. Lissauer, D.G. Monet, D. Morrison, D. Sasselov, J. Tarter, A. Boss, D. Brownlee, T. Owen, D. Buzasi, D. Charbonneau, L. Doyle, J. Fortney, E.B. Ford, M.J. Holman, S. Seager, J.H. Steffen, W.F. Welsh, J. Rowe, H. Anderson, L. Buchhave, D. Ciardi, L. Walkowicz, W. Sherry, E. Horch, H. Isaacson, M.E. Everett, D. Fischer, G. Torres, J.A. Johnson, M. Endl, P. MacQueen, S.T. Bryson, J. Dotson, M. Haas, J. Kolodziejczak, J. Van Cleve, H. Chandrasekaran, J.D. Twicken, E.V. Quintana, B.D. Clarke, C. Allen, J. Li, H. Wu, P. Tenenbaum, E. Verner, F. Bruhweiler, J. Barnes, A. Prsa, Kepler planet-detection mission: introduction and first results. Science 327, 977 (2010). doi:10.1126/science.1185402

    ADS  Google Scholar 

  17. W.J. Borucki, D.G. Koch, G. Basri, N. Batalha, T.M. Brown, S.T. Bryson, D. Caldwell, J. Christensen-Dalsgaard, W.D. Cochran, E. DeVore, E.W. Dunham, T.N. Gautier III, J.C. Geary, R. Gilliland, A. Gould, S.B. Howell, J.M. Jenkins, D.W. Latham, J.J. Lissauer, G.W. Marcy, J. Rowe, D. Sasselov, A. Boss, D. Charbonneau, D. Ciardi, L. Doyle, A.K. Dupree, E.B. Ford, J. Fortney, M.J. Holman, S. Seager, J.H. Steffen, J. Tarter, W.F. Welsh, C. Allen, L.A. Buchhave, J.L. Christiansen, B.D. Clarke, S. Das, J.-M. Désert, M. Endl, D. Fabrycky, F. Fressin, M. Haas, E. Horch, A. Howard, H. Isaacson, H. Kjeldsen, J. Kolodziejczak, C. Kulesa, J. Li, P.W. Lucas, P. Machalek, D. McCarthy, P. MacQueen, S. Meibom, T. Miquel, A. Prsa, S.N. Quinn, E.V. Quintana, D. Ragozzine, W. Sherry, A. Shporer, P. Tenenbaum, G. Torres, J.D. Twicken, J. Van Cleve, L. Walkowicz, F.C. Witteborn, M. Still, Characteristics of planetary candidates observed by Kepler. II. Analysis of the first four months of data. Astrophys. J. 736, 19 (2011). doi:10.1088/0004-637X/736/1/19

    ADS  Google Scholar 

  18. W.J. Borucki, E. Agol, F. Fressin, L. Kaltenegger, J. Rowe, H. Isaacson, D. Fischer, N. Batalha, J.J. Lissauer, G.W. Marcy, D. Fabrycky, J.-M. Désert, S.T. Bryson, T. Barclay, F. Bastien, A. Boss, E. Brugamyer, L.A. Buchhave, C. Burke, D.A. Caldwell, J. Carter, D. Charbonneau, J.R. Crepp, J. Christensen-Dalsgaard, J.L. Christiansen, D. Ciardi, W.D. Cochran, E. DeVore, L. Doyle, A.K. Dupree, M. Endl, M.E. Everett, E.B. Ford, J. Fortney, T.N. Gautier, J.C. Geary, A. Gould, M. Haas, C. Henze, A.W. Howard, S.B. Howell, D. Huber, J.M. Jenkins, H. Kjeldsen, R. Kolbl, J. Kolodziejczak, D.W. Latham, B.L. Lee, E. Lopez, F. Mullally, J.A. Orosz, A. Prsa, E.V. Quintana, R. Sanchis-Ojeda, D. Sasselov, S. Seader, A. Shporer, J.H. Steffen, M. Still, P. Tenenbaum, S.E. Thompson, G. Torres, J.D. Twicken, W.F. Welsh, J.N. Winn, Kepler-62: a five-planet system with planets of 1.4 and 1.6 Earth radii in the habitable zone. Science 340, 587–590 (2013). doi:10.1126/science.1234702

    ADS  Google Scholar 

  19. F. Bouchy, R.F. Díaz, G. Hébrard, L. Arnold, I. Boisse, X. Delfosse, S. Perruchot, A. Santerne, SOPHIE+: first results of an octagonal-section fiber for high-precision radial velocity measurements. Astron. Astrophys. 549, 49 (2013). doi:10.1051/0004-6361/201219979

    ADS  Google Scholar 

  20. T.M. Brown, D. Charbonneau, R.L. Gilliland, R.W. Noyes, A. Burrows, Hubble space telescope time-series photometry of the transiting planet of HD 209458. Astrophys. J. 552, 699–709 (2001). doi:10.1086/320580

    ADS  Google Scholar 

  21. T.M. Brown, D.W. Latham, M.E. Everett, G.A. Esquerdo, Kepler input catalog: photometric calibration and stellar classification. Astron. J. 142, 112 (2011). doi:10.1088/0004-6256/142/4/112

    ADS  Google Scholar 

  22. L.A. Buchhave, D.W. Latham, A. Johansen, M. Bizzarro, G. Torres, J.F. Rowe, N.M. Batalha, W.J. Borucki, E. Brugamyer, C. Caldwell, S.T. Bryson, D.R. Ciardi, W.D. Cochran, M. Endl, G.A. Esquerdo, E.B. Ford, J.C. Geary, R.L. Gilliland, T. Hansen, H. Isaacson, J.B. Laird, P.W. Lucas, G.W. Marcy, J.A. Morse, P. Robertson, A. Shporer, R.P. Stefanik, M. Still, S.N. Quinn, An abundance of small exoplanets around stars with a wide range of metallicities. Nature 486, 375–377 (2012). doi:10.1038/nature11121

    ADS  Google Scholar 

  23. R.P. Butler, G.W. Marcy, E. Williams, C. McCarthy, P. Dosanjh, S.S. Vogt, Attaining Doppler precision of 3 M s-1. Publ. Astron. Soc. Pac. 108, 500 (1996). doi:10.1086/133755

    ADS  Google Scholar 

  24. R.P. Butler, C.G. Tinney, G.W. Marcy, H.R.A. Jones, A.J. Penny, K. Apps, Two new planets from the Anglo-Australian planet search. Astrophys. J. 555, 410–417 (2001). doi:10.1086/321467

    ADS  Google Scholar 

  25. A.G.W. Cameron, The partial volatilization of Mercury. Icarus 64, 285–294 (1985). doi:10.1016/0019-1035(85)90091-0

    ADS  Google Scholar 

  26. R.M. Canup, W.R. Ward, A common mass scaling for satellite systems of gaseous planets. Nature 441, 834–839 (2006). doi:10.1038/nature04860

    ADS  Google Scholar 

  27. J. Chambers, A semi-analytic model for oligarchic growth. Icarus 180, 496–513 (2006). doi:10.1016/j.icarus.2005.10.017

    ADS  Google Scholar 

  28. S. Charpinet, G. Fontaine, P. Brassard, E.M. Green, V. Van Grootel, S.K. Randall, R. Silvotti, A.S. Baran, R.H. Østensen, S.D. Kawaler, J.H. Telting, A compact system of small planets around a former red-giant star. Nature 480, 496–499 (2011). doi:10.1038/nature10631

    ADS  Google Scholar 

  29. E. Chiang, G. Laughlin, The minimum-mass extrasolar nebula: in-situ formation of close-in super-Earths. Mon. Not. R. Astron. Soc. 431, 3444 (2013). doi:10.1093/mnras/stt424

    ADS  Google Scholar 

  30. E. Chiang, A.N. Youdin, Forming planetesimals in solar and extrasolar nebulae. Annu. Rev. Earth Planet. Sci. 38, 493–522 (2010). doi:10.1146/annurev-earth-040809-152513

    ADS  Google Scholar 

  31. M.C. Clampin, Status of the James Webb space telescope observatory, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol. 8442 (2012). doi:10.1117/12.926429

    Google Scholar 

  32. K.D. Colón, E.B. Ford, R.C. Morehead, Constraining the false positive rate for Kepler planet candidates with multicolour photometry from the GTC. Mon. Not. R. Astron. Soc. 426, 342–353 (2012). doi:10.1111/j.1365-2966.2012.21711.x

    ADS  Google Scholar 

  33. R. Cosentino, C. Lovis, F. Pepe, A. Collier Cameron, D.W. Latham, E. Molinari, S. Udry, N. Bezawada, M. Black, A. Born, N. Buchschacher, D. Charbonneau, P. Figueira, M. Fleury, A. Galli, A. Gallie, X. Gao, A. Ghedina, C. Gonzalez, M. Gonzalez, J. Guerra, D. Henry, K. Horne, I. Hughes, D. Kelly, M. Lodi, D. Lunney, C. Maire, M. Mayor, G. Micela, M.P. Ordway, J. Peacock, D. Phillips, G. Piotto, D. Pollacco, D. Queloz, K. Rice, C. Riverol, L. Riverol, J. San Juan, D. Sasselov, D. Segransan, A. Sozzetti, D. Sosnowska, B. Stobie, A. Szentgyorgyi, A. Vick, L. Weber, Harps-N: the new planet hunter at TNG, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol. 8446 (2012). doi:10.1117/12.925738

    Google Scholar 

  34. N.B. Cowan, E. Agol, The statistics of Albedo and heat recirculation on hot exoplanets. Astrophys. J. 729, 54 (2011). doi:10.1088/0004-637X/729/1/54

    ADS  Google Scholar 

  35. A.N. Cox, C.A. Pilachowski, Allen’s astrophysical quantities. Phys. Today 53(10), 100000 (2000). doi:10.1063/1.1325201

    Google Scholar 

  36. M. Ćuk, J.A. Burns, On the secular behavior of irregular satellites. Astron. J. 128, 2518–2541 (2004). doi:10.1086/424937

    ADS  Google Scholar 

  37. A. Dalgarno, F.J. Smith, The thermal conductivity and viscosity of atomic oxygen. Planet. Space Sci. 9, 1 (1962). doi:10.1016/0032-0633(62)90064-8

    ADS  Google Scholar 

  38. B.-O. Demory, M. Gillon, S. Seager, B. Benneke, D. Deming, B. Jackson, Detection of thermal emission from a super-Earth. Astrophys. J. Lett. 751, 28 (2012). doi:10.1088/2041-8205/751/2/L28

    ADS  Google Scholar 

  39. A. Dressler, D. Spergel, M. Mountain, M. Postman, E. Elliott, E. Bendek, D. Bennett, J. Dalcanton, S. Gaudi, N. Gehrels, O. Guyon, C. Hirata, J. Kalirai, N.J. Kasdin, J. Kruk, B. Macintosh, S. Malhotra, M. Penny, S. Perlmutter, G. Rieke, A. Riess, J. Rhoads, S. Shaklan, R. Somerville, D. Stern, R. Thompson, D. Weinberg, Exploring the NRO opportunity for a Hubble-sized wide-field near-IR space telescope—NEW WFIRST (2012). arXiv e-prints

  40. X. Dumusque, S. Udry, C. Lovis, N.C. Santos, M.J.P.F.G. Monteiro, Planetary detection limits taking into account stellar noise. I. Observational strategies to reduce stellar oscillation and granulation effects. Astron. Astrophys. 525, 140 (2011). doi:10.1051/0004-6361/201014097

    ADS  Google Scholar 

  41. X. Dumusque, F. Pepe, C. Lovis, D. Ségransan, J. Sahlmann, W. Benz, F. Bouchy, M. Mayor, D. Queloz, N. Santos, S. Udry, An Earth-mass planet orbiting α Centauri B. Nature 491, 207–211 (2012). doi:10.1038/nature11572

    ADS  Google Scholar 

  42. D.S. Ebel, C.M.O. Alexander, Equilibrium condensation from chondritic porous IDP enriched vapor: implications for Mercury and enstatite chondrite origins. Planet. Space Sci. 59, 1888–1894 (2011). doi:10.1016/j.pss.2011.07.017

    ADS  Google Scholar 

  43. S. Elser, B. Moore, J. Stadel, R. Morishima, How common are Earth-Moon planetary systems? Icarus 214, 357–365 (2011). doi:10.1016/j.icarus.2011.05.025

    ADS  Google Scholar 

  44. M. Endl, M. Kürster, S. Els, The planet search program at the ESO Coudé Echelle spectrometer. I. Data modeling technique and radial velocity precision tests. Astron. Astrophys. 362, 585–594 (2000)

    ADS  Google Scholar 

  45. B. Fegley, A.G.W. Cameron, A vaporization model for iron/silicate fractionation in the Mercury protoplanet. Earth Planet. Sci. Lett. 82, 207–222 (1987). doi:10.1016/0012-821X(87)90196-8

    ADS  Google Scholar 

  46. M.J. Fogg, R.P. Nelson, The effect of type I migration on the formation of terrestrial planets in hot-Jupiter systems. Astron. Astrophys. 472, 1003–1015 (2007). doi:10.1051/0004-6361:20077950

    ADS  Google Scholar 

  47. E.B. Ford, J.F. Rowe, D.C. Fabrycky, J.A. Carter, M.J. Holman, J.J. Lissauer, D. Ragozzine, J.H. Steffen, N.M. Batalha, W.J. Borucki, S. Bryson, D.A. Caldwell, E.W. Dunham, T.N. Gautier III, J.M. Jenkins, D.G. Koch, J. Li, P. Lucas, G.W. Marcy, S. McCauliff, F.R. Mullally, E. Quintana, M. Still, P. Tenenbaum, S.E. Thompson, J.D. Twicken, Transit timing observations from Kepler. I. Statistical analysis of the first four months. Astrophys. J. Suppl. Ser. 197, 2 (2011). doi:10.1088/0067-0049/197/1/2

    ADS  Google Scholar 

  48. F. Fressin, G. Torres, J.F. Rowe, D. Charbonneau, L.A. Rogers, S. Ballard, N.M. Batalha, W.J. Borucki, S.T. Bryson, L.A. Buchhave, D.R. Ciardi, J.-M. Désert, C.D. Dressing, D.C. Fabrycky, E.B. Ford, T.N. Gautier III, C.E. Henze, M.J. Holman, A. Howard, S.B. Howell, J.M. Jenkins, D.G. Koch, D.W. Latham, J.J. Lissauer, G.W. Marcy, S.N. Quinn, D. Ragozzine, D.D. Sasselov, S. Seager, T. Barclay, F. Mullally, S.E. Seader, M. Still, J.D. Twicken, S.E. Thompson, K. Uddin, Two earth-sized planets orbiting Kepler-20. Nature 482, 195–198 (2012). doi:10.1038/nature10780

    ADS  Google Scholar 

  49. F. Fressin, G. Torres, D. Charbonneau, S.T. Bryson, J. Christiansen, C.D. Dressing, J.M. Jenkins, L.M. Walkowicz, N.M. Batalha, The false positive rate of Kepler and the occurrence of planets. Astrophys. J. 766, 81 (2013). doi:10.1088/0004-637X/766/2/81

    ADS  Google Scholar 

  50. B.J. Fulton, A. Shporer, J.N. Winn, M.J. Holman, A. Pál, J.Z. Gazak, Long-term transit timing monitoring and refined light curve parameters of HAT-P-13b. Astron. J. 142, 84 (2011). doi:10.1088/0004-6256/142/3/84

    ADS  Google Scholar 

  51. E. Gaidos, D.M. Williams, Seasonality on terrestrial extrasolar planets: inferring obliquity and surface conditions from infrared light curves. New Astron. 10, 67–77 (2004). doi:10.1016/j.newast.2004.04.009

    ADS  Google Scholar 

  52. E. Gaidos, D.A. Fischer, A.W. Mann, S. Lépine, On the nature of small planets around the coolest Kepler stars. Astrophys. J. 746, 36 (2012). doi:10.1088/0004-637X/746/1/36

    ADS  Google Scholar 

  53. R.L. Gilliland, W.J. Chaplin, E.W. Dunham, V.S. Argabright, W.J. Borucki, G. Basri, S.T. Bryson, D.L. Buzasi, D.A. Caldwell, Y.P. Elsworth, J.M. Jenkins, D.G. Koch, J. Kolodziejczak, A. Miglio, J. van Cleve, L.M. Walkowicz, W.F. Welsh, Kepler mission stellar and instrument noise properties. Astrophys. J. Suppl. Ser. 197, 6 (2011). doi:10.1088/0067-0049/197/1/6

    ADS  Google Scholar 

  54. B. Gladman, J. Coffey, Mercurian impact ejecta: meteorites and mantle. Meteorit. Planet. Sci. 44, 285–291 (2009). doi:10.1111/j.1945-5100.2009.tb00734.x

    ADS  Google Scholar 

  55. Y.-X. Gong, J.-L. Zhou, J.-W. Xie, X.-M. Wu, The effect of planet-planet scattering on the survival of exomoons. Astrophys. J. Lett. 769, 14 (2013). doi:10.1088/2041-8205/769/1/L14

    ADS  Google Scholar 

  56. O. Grasset, J. Schneider, C. Sotin, A study of the accuracy of mass-radius relationships for silicate-rich and ice-rich planets up to 100 Earth masses. Astrophys. J. 693, 722–733 (2009). doi:10.1088/0004-637X/693/1/722

    ADS  Google Scholar 

  57. S. Guilloteau, A. Dutrey, V. Piétu, Y. Boehler, A dual-frequency sub-arcsecond study of proto-planetary disks at mm wavelengths: first evidence for radial variations of the dust properties. Astron. Astrophys. 529, 105 (2011). doi:10.1051/0004-6361/201015209

    ADS  Google Scholar 

  58. N. Haghighipour, The formation and dynamics of super-Earth planets. Annu. Rev. Earth Planet. Sci. 41, 469–495 (2013). doi:10.1146/annurev-earth-042711-105340

    ADS  Google Scholar 

  59. B.M.S. Hansen, H.-Y. Shih, T. Currie, The pulsar planets: a test case of terrestrial planet assembly. Astrophys. J. 691, 382–393 (2009). doi:10.1088/0004-637X/691/1/382

    ADS  Google Scholar 

  60. A.P. Hatzes, The radial velocity detection of Earth-mass planets in the presence of activity noise: the case of α Centauri Bb. Astrophys. J. 770, 133 (2013). doi:10.1088/0004-637X/770/2/133

    ADS  Google Scholar 

  61. S.A. Hauck, J.-L. Margot, S.C. Solomon, R.J. Phillips, C.L. Johnson, F.G. Lemoine, E. Mazarico, T.J. McCoy, S. Padovan, S.J. Peale, M.E. Perry, D.E. Smith, M.T. Zuber, The curious case of Mercury’s internal structure. J. Geophys. Res. 118, 1204–1220 (2013). doi:10.1002/jgre.20091

    Google Scholar 

  62. C. Hayashi, Structure of the solar nebula, growth and decay of magnetic fields and effects of magnetic and turbulent viscosities on the nebula. Prog. Theor. Phys. Suppl. 70, 35–53 (1981). doi:10.1143/PTPS.70.35

    ADS  Google Scholar 

  63. G. Hébrard, A. Lecavelier Des Étangs, A. Vidal-Madjar, J.-M. Désert, R. Ferlet, Evaporation rate of hot Jupiters and formation of Chthonian planets, in Extrasolar Planets: Today and Tomorrow, ed. by J. Beaulieu, A. Lecavelier Des Etangs, C. Terquem. Astronomical Society of the Pacific Conference Series, vol. 321, (2004), p. 203

    Google Scholar 

  64. T. Hirano, N. Narita, B. Sato, Y.H. Takahashi, K. Masuda, Y. Takeda, W. Aoki, M. Tamura, Y. Suto, Planet-planet eclipse and the Rossiter-McLaughlin effect of a multiple transiting system: joint analysis of the Subaru spectroscopy and the Kepler photometry. Astrophys. J. Lett. 759, 36 (2012). doi:10.1088/2041-8205/759/2/L36

    ADS  Google Scholar 

  65. M.J. Holman, N.W. Murray, The use of transit timing to detect terrestrial-mass extrasolar planets. Science 307, 1288–1291 (2005). doi:10.1126/science.1107822

    ADS  Google Scholar 

  66. A.W. Howard, G.W. Marcy, J.A. Johnson, D.A. Fischer, J.T. Wright, H. Isaacson, J.A. Valenti, J. Anderson, D.N.C. Lin, S. Ida, The occurrence and mass distribution of close-in super-Earths, Neptunes, and Jupiters. Science 330, 653 (2010). doi:10.1126/science.1194854

    ADS  Google Scholar 

  67. A.W. Howard, G.W. Marcy, S.T. Bryson, J.M. Jenkins, J.F. Rowe, N.M. Batalha, W.J. Borucki, D.G. Koch, E.W. Dunham, T.N. Gautier III, J. Van Cleve, W.D. Cochran, D.W. Latham, J.J. Lissauer, G. Torres, T.M. Brown, R.L. Gilliland, L.A. Buchhave, D.A. Caldwell, J. Christensen-Dalsgaard, D. Ciardi, F. Fressin, M.R. Haas, S.B. Howell, H. Kjeldsen, S. Seager, L. Rogers, D.D. Sasselov, J.H. Steffen, G.S. Basri, D. Charbonneau, J. Christiansen, B. Clarke, A. Dupree, D.C. Fabrycky, D.A. Fischer, E.B. Ford, J.J. Fortney, J. Tarter, F.R. Girouard, M.J. Holman, J.A. Johnson, T.C. Klaus, P. Machalek, A.V. Moorhead, R.C. Morehead, D. Ragozzine, P. Tenenbaum, J.D. Twicken, S.N. Quinn, H. Isaacson, A. Shporer, P.W. Lucas, L.M. Walkowicz, W.F. Welsh, A. Boss, E. Devore, A. Gould, J.C. Smith, R.L. Morris, A. Prsa, T.D. Morton, M. Still, S.E. Thompson, F. Mullally, M. Endl, P.J. MacQueen, Planet occurrence within 0.25 AU of solar-type stars from Kepler. Astrophys. J. Suppl. Ser. 201, 15 (2012). doi:10.1088/0067-0049/201/2/15

    ADS  Google Scholar 

  68. S. Ida, D.N.C. Lin, Toward a deterministic model of planetary formation. VI. Dynamical interaction and coagulation of multiple rocky embryos and super-Earth systems around solar-type stars. Astrophys. J. Lett. 719, 810–830 (2010). doi:10.1088/0004-637X/719/1/810

    ADS  Google Scholar 

  69. A. Isella, J.M. Carpenter, A.I. Sargent, Structure and evolution of pre-main-sequence circumstellar disks. Astrophys. J. Lett. 701, 260–282 (2009). doi:10.1088/0004-637X/701/1/260

    ADS  Google Scholar 

  70. J.M. Jenkins, D.A. Caldwell, H. Chandrasekaran, J.D. Twicken, S.T. Bryson, E.V. Quintana, B.D. Clarke, J. Li, C. Allen, P. Tenenbaum, H. Wu, T.C. Klaus, C.K. Middour, M.T. Cote, S. McCauliff, F.R. Girouard, J.P. Gunter, B. Wohler, J. Sommers, J.R. Hall, A.K. Uddin, M.S. Wu, P.A. Bhavsar, J. Van Cleve, D.L. Pletcher, J.A. Dotson, M.R. Haas, R.L. Gilliland, D.G. Koch, W.J. Borucki, Overview of the Kepler science processing pipeline. Astrophys. J. Lett. 713, 87–91 (2010). doi:10.1088/2041-8205/713/2/L87

    ADS  Google Scholar 

  71. R.E. Johnson, Thermally driven atmospheric escape. Astrophys. J. Lett. 716, 1573–1578 (2010). doi:10.1088/0004-637X/716/2/1573

    ADS  Google Scholar 

  72. E. Kambe, H. Ando, B. Sato, H. Izumiura, T. Sekii, D.B. Paulson, K. Yanagisawa, S. Masuda, H. Shibahashi, A.P. Hatzes, M. Martic, J.-C. Lebrun, D.E. Mkrtichian, L.L. Kiss, H. Bruntt, S.J. O’Toole, T.R. Bedding, Development of iodine cells for Subaru HDS and Okayama HIDES. III. An improvement on the radial-velocity measurement technique. Publ. Astron. Soc. Jpn. 60, 45 (2008)

    ADS  Google Scholar 

  73. G.M. Kennedy, S.J. Kenyon, Planet formation around stars of various masses: hot super-Earths. Astrophys. J. 682, 1264–1276 (2008). doi:10.1086/589436

    ADS  Google Scholar 

  74. S.J. Kenyon, B.C. Bromley, Terrestrial planet formation. I. The transition from oligarchic growth to chaotic growth. Astron. J. 131, 1837–1850 (2006). doi:10.1086/499807

    ADS  Google Scholar 

  75. D.M. Kipping, S.J. Fossey, G. Campanella, On the detectability of habitable exomoons with Kepler-class photometry. Mon. Not. R. Astron. Soc. 400, 398–405 (2009). doi:10.1111/j.1365-2966.2009.15472.x

    ADS  Google Scholar 

  76. D.M. Kipping, J. Hartman, L.A. Buchhave, A.R. Schmitt, G.Á. Bakos, D. Nesvorný, The hunt for exomoons with Kepler (HEK). II. Analysis of seven viable satellite-hosting planet candidates. Astrophys. J. 770, 101 (2013). doi:10.1088/0004-637X/770/2/101

    ADS  Google Scholar 

  77. D.G. Koch, W.J. Borucki, G. Basri, N.M. Batalha, T.M. Brown, D. Caldwell, J. Christensen-Dalsgaard, W.D. Cochran, E. DeVore, E.W. Dunham, T.N. Gautier III, J.C. Geary, R.L. Gilliland, A. Gould, J. Jenkins, Y. Kondo, D.W. Latham, J.J. Lissauer, G. Marcy, D. Monet, D. Sasselov, A. Boss, D. Brownlee, J. Caldwell, A.K. Dupree, S.B. Howell, H. Kjeldsen, S. Meibom, D. Morrison, T. Owen, H. Reitsema, J. Tarter, S.T. Bryson, J.L. Dotson, P. Gazis, M.R. Haas, J. Kolodziejczak, J.F. Rowe, J.E. Van Cleve, C. Allen, H. Chandrasekaran, B.D. Clarke, J. Li, E.V. Quintana, P. Tenenbaum, J.D. Twicken, H. Wu, Kepler mission design, realized photometric performance, and early science. Astrophys. J. Lett. 713, 79–86 (2010). doi:10.1088/2041-8205/713/2/L79

    ADS  Google Scholar 

  78. E. Kokubo, S. Ida, Oligarchic growth of protoplanets. Icarus 131, 171–178 (1998). doi:10.1006/icar.1997.5840

    ADS  Google Scholar 

  79. E. Kokubo, S. Ida, Formation of protoplanets from planetesimals in the solar nebula. Icarus 143, 15–27 (2000). doi:10.1006/icar.1999.6237

    ADS  Google Scholar 

  80. E. Kokubo, J. Kominami, S. Ida, Formation of terrestrial planets from protoplanets. I. Statistics of basic dynamical properties. Astrophys. J. 642, 1131–1139 (2006). doi:10.1086/501448

    ADS  Google Scholar 

  81. D. Kubas, J.P. Beaulieu, D.P. Bennett, A. Cassan, A. Cole, J. Lunine, J.B. Marquette, S. Dong, A. Gould, T. Sumi, V. Batista, P. Fouqué, S. Brillant, S. Dieters, C. Coutures, J. Greenhill, I. Bond, T. Nagayama, A. Udalski, E. Pompei, D.E.A. Nürnberger, J.B. Le Bouquin, A frozen super-Earth orbiting a star at the bottom of the main sequence. Astron. Astrophys. 540, 78 (2012). doi:10.1051/0004-6361/201015832

    ADS  Google Scholar 

  82. M.J. Kuchner, Volatile-rich Earth-mass planets in the habitable zone. Astrophys. J. 596, 105–108 (2003). doi:10.1086/378397

    ADS  Google Scholar 

  83. A. Léger, F. Selsis, C. Sotin, T. Guillot, D. Despois, D. Mawet, M. Ollivier, A. Labèque, C. Valette, F. Brachet, B. Chazelas, H. Lammer, A new family of planets? “Ocean-planets”. Icarus 169, 499–504 (2004). doi:10.1016/j.icarus.2004.01.001

    ADS  Google Scholar 

  84. A. Léger, O. Grasset, B. Fegley, F. Codron, A.F. Albarede, P. Barge, R. Barnes, P. Cance, S. Carpy, F. Catalano, C. Cavarroc, O. Demangeon, S. Ferraz-Mello, P. Gabor, J.-M. Grießmeier, J. Leibacher, G. Libourel, A.-S. Maurin, S.N. Raymond, D. Rouan, B. Samuel, L. Schaefer, J. Schneider, P.A. Schuller, F. Selsis, C. Sotin, The extreme physical properties of the CoRoT-7b super-Earth. Icarus 213, 1–11 (2011). doi:10.1016/j.icarus.2011.02.004

    ADS  Google Scholar 

  85. J.S. Lewis, Metal/silicate fractionation in the solar system. Earth Planet. Sci. Lett. 15, 286–290 (1972). doi:10.1016/0012-821X(72)90174-4

    ADS  Google Scholar 

  86. N.K. Lewis, A.P. Showman, J.J. Fortney, M.S. Marley, R.S. Freedman, K. Lodders, Atmospheric circulation of eccentric hot Neptune GJ436b. Astrophys. J. 720, 344–356 (2010). doi:10.1088/0004-637X/720/1/344

    ADS  Google Scholar 

  87. C.-H. Li, A.G. Glenday, D.F. Phillips, G. Furesz, N. Langellier, M. Webber, A. Zibrov, A.J. Benedick, G. Chang, L.-J. Chen, D. Sasselov, F. Kärtner, A. Szentgyorgyi, R.L. Walsworth, Green astro-comb for HARPS-N, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol. 8446 (2012). doi:10.1117/12.925799

    Google Scholar 

  88. D.N.C. Lin, P. Bodenheimer, D.C. Richardson, Orbital migration of the planetary companion of 51 Pegasi to its present location. Nature 380, 606–607 (1996). doi:10.1038/380606a0

    ADS  Google Scholar 

  89. J.J. Lissauer, D. Ragozzine, D.C. Fabrycky, J.H. Steffen, E.B. Ford, J.M. Jenkins, A. Shporer, M.J. Holman, J.F. Rowe, E.V. Quintana, N.M. Batalha, W.J. Borucki, S.T. Bryson, D.A. Caldwell, J.A. Carter, D. Ciardi, E.W. Dunham, J.J. Fortney, T.N. Gautier III, S.B. Howell, D.G. Koch, D.W. Latham, G.W. Marcy, R.C. Morehead, D. Sasselov, Architecture and dynamics of Kepler’s candidate multiple transiting planet systems. Astrophys. J. Suppl. Ser. 197, 8 (2011). doi:10.1088/0067-0049/197/1/8

    ADS  Google Scholar 

  90. C. Lovis, M. Mayor, F. Pepe, Y. Alibert, W. Benz, F. Bouchy, A.C.M. Correia, J. Laskar, C. Mordasini, D. Queloz, N.C. Santos, S. Udry, J.-L. Bertaux, J.-P. Sivan, An extrasolar planetary system with three Neptune-mass planets. Nature 441, 305–309 (2006). doi:10.1038/nature04828

    ADS  Google Scholar 

  91. G. Maciejewski, D. Dimitrov, M. Seeliger, S. Raetz, Ł. Bukowiecki, M. Kitze, R. Errmann, G. Nowak, A. Niedzielski, V. Popov, C. Marka, K. Goździewski, R. Neuhäuser, J. Ohlert, T.C. Hinse, J.W. Lee, C.-U. Lee, J.-N. Yoon, A. Berndt, H. Gilbert, C. Ginski, M.M. Hohle, M. Mugrauer, T. Röll, T.O.B. Schmidt, N. Tetzlaff, L. Mancini, J. Southworth, M. Dall’Ora, S. Ciceri, R. Zambelli, G. Corfini, H. Takahashi, K. Tachihara, J.M. Benkő, K. Sárneczky, G.M. Szabo, T.N. Varga, M. Vaňko, Y.C. Joshi, W.P. Chen, Multi-site campaign for transit timing variations of WASP-12 b: possible detection of a long-period signal of planetary origin. Astron. Astrophys. 551, 108 (2013). doi:10.1051/0004-6361/201220739

    ADS  Google Scholar 

  92. A.M. Mandell, S.N. Raymond, S. Sigurdsson, Formation of Earth-like planets during and after giant planet migration. Astrophys. J. 660, 823–844 (2007). doi:10.1086/512759

    ADS  Google Scholar 

  93. A.W. Mann, E. Gaidos, S. Lépine, E.J. Hilton, They might be giants: luminosity class, planet occurrence, and planet-metallicity relation of the coolest Kepler target stars. Astrophys. J. 753, 90 (2012). doi:10.1088/0004-637X/753/1/90

    ADS  Google Scholar 

  94. A.W. Mann, E. Gaidos, A. Kraus, E.J. Hilton, Testing the metal of late-type Kepler planet hosts with iron-clad methods. Astrophys. J. 770, 43 (2013). doi:10.1088/0004-637X/770/1/43

    ADS  Google Scholar 

  95. S. Mao, B. Paczynski, Gravitational microlensing by double stars and planetary systems. Astrophys. J. 374, 37–40 (1991). doi:10.1086/186066

    ADS  Google Scholar 

  96. M. Mayor, D. Queloz, A Jupiter-mass companion to a solar-type star. Nature 378, 355–359 (1995). doi:10.1038/378355a0

    ADS  Google Scholar 

  97. Y. Miguel, L. Kaltenegger, B. Fegley, L. Schaefer, Compositions of hot super-Earth atmospheres: exploring Kepler candidates. Astrophys. J. 742, 19 (2011). doi:10.1088/2041-8205/742/2/L19

    ADS  Google Scholar 

  98. M.C. Miller, D.P. Hamilton, Implications of the PSR 1257+12 planetary system for isolated millisecond pulsars. Astrophys. J. 550, 863–870 (2001). doi:10.1086/319813

    ADS  Google Scholar 

  99. J. Miralda-Escudé, Orbital perturbations of transiting planets: a possible method to measure stellar quadrupoles and to detect Earth-mass planets. Astrophys. J. 564, 1019–1023 (2002). doi:10.1086/324279

    ADS  Google Scholar 

  100. R. Montgomery, G. Laughlin, Formation and detection of Earth mass planets around low mass stars. Icarus 202, 1–11 (2009). doi:10.1016/j.icarus.2009.02.035

    ADS  Google Scholar 

  101. A. Morbidelli, J.I. Lunine, D.P. O’Brien, S.N. Raymond, K.J. Walsh, Building terrestrial planets. Annu. Rev. Earth Planet. Sci. 40, 251–275 (2012). doi:10.1146/annurev-earth-042711-105319

    ADS  Google Scholar 

  102. T.D. Morton, An efficient automated validation procedure for exoplanet transit candidates. Astrophys. J. 761, 6 (2012). doi:10.1088/0004-637X/761/1/6

    ADS  Google Scholar 

  103. P.S. Muirhead, K. Hamren, E. Schlawin, B. Rojas-Ayala, K.R. Covey, J.P. Lloyd, Characterizing the cool Kepler objects of interests. New effective temperatures, metallicities, masses, and radii of low-mass Kepler planet-candidate host stars. Astrophys. J. 750, 37 (2012a). doi:10.1088/2041-8205/750/2/L37

    ADS  Google Scholar 

  104. P.S. Muirhead, J.A. Johnson, K. Apps, J.A. Carter, T.D. Morton, D.C. Fabrycky, J.S. Pineda, M. Bottom, B. Rojas-Ayala, E. Schlawin, K. Hamren, K.R. Covey, J.R. Crepp, K.G. Stassun, J. Pepper, L. Hebb, E.N. Kirby, A.W. Howard, H.T. Isaacson, G.W. Marcy, D. Levitan, T. Diaz-Santos, L. Armus, J.P. Lloyd, Characterizing the cool KOIs. III. KOI 961: a small star with large proper motion and three small planets. Astrophys. J. 747, 144 (2012b). doi:10.1088/0004-637X/747/2/144

    ADS  Google Scholar 

  105. D.P. O’Brien, A. Morbidelli, H.F. Levison, Terrestrial planet formation with strong dynamical friction. Icarus 184, 39–58 (2006). doi:10.1016/j.icarus.2006.04.005

    ADS  Google Scholar 

  106. M. Ogihara, S. Ida, N-body simulations of satellite formation around giant planets: origin of orbital configuration of the Galilean moons. Astrophys. J. 753, 60 (2012)

    ADS  Google Scholar 

  107. A. Pál, Light-curve modelling for mutual transits. Mon. Not. R. Astron. Soc. 420, 1630–1635 (2012). doi:10.1111/j.1365-2966.2011.20151.x

    ADS  Google Scholar 

  108. L. Pasquini, S. Cristiani, R. García López, M. Haehnelt, M. Mayor, J. Liske, A. Manescau, G. Avila, H. Dekker, O. Iwert, B. Delabre, G. Lo Curto, V. D’Odorico, P. Molaro, M. Viel, E. Vanzella, P. Bonifacio, P. di Marcantonio, P. Santin, M. Comari, R. Cirami, I. Coretti, F.M. Zerbi, P. Spanò, M. Riva, R. Rebolo, G. Israelian, A. Herrero, M.R. Zapatero Osorio, F. Tenegi, B. Carswell, G. Becker, S. Udry, F. Pepe, C. Lovis, D. Naef, M. Dessauges, D. Mégevand, Codex, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol. 7735 (2010). doi:10.1117/12.856974

    Google Scholar 

  109. M.T. Penny, E. Kerins, N. Rattenbury, J.-P. Beaulieu, A.C. Robin, S. Mao, V. Batista, S. Calchi Novati, A. Cassan, P. Fouqué, I. McDonald, J.B. Marquette, P. Tisserand, M.R. Zapatero Osorio, ExELS: an exoplanet legacy science proposal for the ESA Euclid mission—I. Cold exoplanets. Mon. Not. R. Astron. Soc. 434, 2 (2013). doi:10.1093/mnras/stt927

    ADS  Google Scholar 

  110. F.A. Pepe, S. Cristiani, R. Rebolo Lopez, N.C. Santos, A. Amorim, G. Avila, W. Benz, P. Bonifacio, A. Cabral, P. Carvas, R. Cirami, J. Coelho, M. Comari, I. Coretti, V. de Caprio, H. Dekker, B. Delabre, P. di Marcantonio, V. D’Odorico, M. Fleury, R. García, J.M. Herreros Linares, I. Hughes, O. Iwert, J. Lima, J.-L. Lizon, G. Lo Curto, C. Lovis, A. Manescau, C. Martins, D. Mégevand, A. Moitinho, P. Molaro, M. Monteiro, M. Monteiro, L. Pasquini, C. Mordasini, D. Queloz, J.L. Rasilla, J.M. Rebordão, S. Santana Tschudi, P. Santin, D. Sosnowska, P. Spanò, F. Tenegi, S. Udry, E. Vanzella, M. Viel, M.R. Zapatero Osorio, F. Zerbi, ESPRESSO: the Echelle spectrograph for rocky exoplanets and stable spectroscopic observations, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol. 7735 (2010). doi:10.1117/12.857122

    Google Scholar 

  111. P.N. Peplowski, L.G. Evans, S.A. Hauck, T.J. McCoy, W.V. Boynton, J.J. Gillis-Davis, D.S. Ebel, J.O. Goldsten, D.K. Hamara, D.J. Lawrence, R.L. McNutt, L.R. Nittler, S.C. Solomon, E.A. Rhodes, A.L. Sprague, R.D. Starr, K.R. Stockstill-Cahill, Radioactive elements on Mercury’s surface from MESSENGER: implications for the planet’s formation and evolution. Science 333, 1850 (2011). doi:10.1126/science.1211576

    ADS  Google Scholar 

  112. E.A. Petigura, G.W. Marcy, A.W. Howard, A plateau in the planet population below twice the size of Earth. Astrophys. J. 770(1), 69 (2013)

    ADS  Google Scholar 

  113. J.A. Phillips, S.E. Thorsett, Planets around pulsars: a review. Astrophys. Space Sci. 212, 91–106 (1994). doi:10.1007/BF00984513

    ADS  Google Scholar 

  114. R. Pierrehumbert, E. Gaidos, Hydrogen greenhouse planets beyond the habitable zone. Astrophys. J. 734, 13 (2011). doi:10.1088/2041-8205/734/1/L13

    ADS  Google Scholar 

  115. F. Pont, R.L. Gilliland, C. Moutou, D. Charbonneau, F. Bouchy, T.M. Brown, M. Mayor, D. Queloz, N. Santos, S. Udry, Hubble space telescope time-series photometry of the planetary transit of HD 189733: no moon, no rings, starspots. Astron. Astrophys. 476, 1347–1355 (2007). doi:10.1051/0004-6361:20078269

    ADS  Google Scholar 

  116. S.B. Porter, W.M. Grundy, Post-capture evolution of potentially habitable exomoons. Astrophys. J. 736, 14 (2011). doi:10.1088/2041-8205/736/1/L14

    ADS  Google Scholar 

  117. D. Queloz, F. Bouchy, C. Moutou, A. Hatzes, G. Hébrard, R. Alonso, M. Auvergne, A. Baglin, M. Barbieri, P. Barge, W. Benz, P. Bordé, H.J. Deeg, M. Deleuil, R. Dvorak, A. Erikson, S. Ferraz Mello, M. Fridlund, D. Gandolfi, M. Gillon, E. Guenther, T. Guillot, L. Jorda, M. Hartmann, H. Lammer, A. Léger, A. Llebaria, C. Lovis, P. Magain, M. Mayor, T. Mazeh, M. Ollivier, M. Pätzold, F. Pepe, H. Rauer, D. Rouan, J. Schneider, D. Segransan, S. Udry, G. Wuchterl, The CoRoT-7 planetary system: two orbiting super-Earths. Astron. Astrophys. 506, 303–319 (2009). doi:10.1051/0004-6361/200913096

    ADS  Google Scholar 

  118. M.V. Radovan, G.F. Cabak, L.H. Laiterman, C.T. Lockwood, S.S. Vogt, A radial velocity spectrometer for the automated planet finder telescope at lick observatory, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol. 7735 (2010). doi:10.1117/12.857726

    Google Scholar 

  119. D. Ragozzine, M.J. Holman, The value of systems with multiple transiting planets (2010). arXiv e-prints

  120. S. Rappaport, A. Levine, E. Chiang, I. El Mellah, J. Jenkins, B. Kalomeni, E.S. Kite, M. Kotson, L. Nelson, L. Rousseau-Nepton, K. Tran, Possible disintegrating short-period super-Mercury orbiting KIC 12557548. Astrophys. J. 752, 1 (2012). doi:10.1088/0004-637X/752/1/1

    ADS  Google Scholar 

  121. S.N. Raymond, A.M. Mandell, S. Sigurdsson, Exotic Earths: forming habitable worlds with giant planet migration. Science 313, 1413–1416 (2006). doi:10.1126/science.1130461

    ADS  Google Scholar 

  122. S.N. Raymond, J. Scalo, V.S. Meadows, A decreased probability of habitable planet formation around low-mass stars. Astrophys. J. 669, 606–614 (2007). doi:10.1086/521587

    ADS  Google Scholar 

  123. S.N. Raymond, R. Barnes, A.M. Mandell, Observable consequences of planet formation models in systems with close-in terrestrial planets. Mon. Not. R. Astron. Soc. 384, 663–674 (2008). doi:10.1111/j.1365-2966.2007.12712.x

    ADS  Google Scholar 

  124. S.N. Raymond, D.P. O’Brien, A. Morbidelli, N.A. Kaib, Building the terrestrial planets: constrained accretion in the inner solar system. Icarus 203, 644–662 (2009). doi:10.1016/j.icarus.2009.05.016

    ADS  Google Scholar 

  125. A. Reiners, J.L. Bean, K.F. Huber, S. Dreizler, A. Seifahrt, S. Czesla, Detecting planets around very low mass stars with the radial velocity method. Astrophys. J. 710, 432–443 (2010). doi:10.1088/0004-637X/710/1/432

    ADS  Google Scholar 

  126. I. Ribas, E.F. Guinan, M. Güdel, M. Audard, Evolution of the solar activity over time and effects on planetary atmospheres. I. High-energy irradiances (1–1700 Å). Astrophys. J. 622, 680–694 (2005). doi:10.1086/427977

    ADS  Google Scholar 

  127. E.J. Rivera, J.J. Lissauer, R.P. Butler, G.W. Marcy, S.S. Vogt, D.A. Fischer, T.M. Brown, G. Laughlin, G.W. Henry, A ∼7.5 M planet orbiting the nearby star, GJ 876. Astrophys. J. 634, 625–640 (2005). doi:10.1086/491669

    ADS  Google Scholar 

  128. L.A. Rogers, S. Seager, A framework for quantifying the degeneracies of exoplanet interior compositions. Astrophys. J. 712, 974–991 (2010). doi:10.1088/0004-637X/712/2/974

    ADS  Google Scholar 

  129. G. Rupprecht, F. Pepe, M. Mayor, D. Queloz, F. Bouchy, G. Avila, W. Benz, J.-L. Bertaux, X. Bonfils, T. Dall, B. Delabre, H. Dekker, W. Eckert, M. Fleury, A. Gilliotte, D. Gojak, J.C. Guzman, D. Kohler, J.-L. Lizon, G. Lo Curto, A. Longinotti, C. Lovis, D. Megevand, L. Pasquini, J. Reyes, J.-P. Sivan, D. Sosnowska, R. Soto, S. Udry, A. Van Kesteren, L. Weber, U. Weilenmann, The exoplanet hunter HARPS: performance and first results, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, ed. by A.F.M. Moorwood, M. Iye, vol. 5492 (2004), pp. 148–159. doi:10.1117/12.551267

    Google Scholar 

  130. R. Sanchis-Ojeda, D.C. Fabrycky, J.N. Winn, T. Barclay, B.D. Clarke, E.B. Ford, J.J. Fortney, J.C. Geary, M.J. Holman, A.W. Howard, J.M. Jenkins, D. Koch, J.J. Lissauer, G.W. Marcy, F. Mullally, D. Ragozzine, S.E. Seader, M. Still, S.E. Thompson, Alignment of the stellar spin with the orbits of a three-planet system. Nature 487, 449–453 (2012). doi:10.1038/nature11301

    ADS  Google Scholar 

  131. J. Sanz-Forcada, G. Micela, I. Ribas, A.M.T. Pollock, C. Eiroa, A. Velasco, E. Solano, D. García-Álvarez, Estimation of the XUV radiation onto close planets and their evaporation. Astron. Astrophys. 532, 6 (2011). doi:10.1051/0004-6361/201116594

    ADS  Google Scholar 

  132. T. Sasaki, G.R. Stewart, S. Ida, Origin of the different architectures of the Jovian and Saturnian satellite systems. Astrophys. J. 714, 1052–1064 (2010). doi:10.1088/0004-637X/714/2/1052

    ADS  Google Scholar 

  133. J. Schneider, C. Dedieu, P. Le Sidaner, R. Savalle, I. Zolotukhin, Defining and cataloging exoplanets: the exoplanet.eu database. Astron. Astrophys. 532, 79 (2011). doi:10.1051/0004-6361/201116713

    ADS  Google Scholar 

  134. C. Schwab, J.F.P. Spronck, A. Tokovinin, A. Szymkowiak, M. Giguere, D.A. Fischer, Performance of the CHIRON high-resolution Echelle spectrograph, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol. 8446 (2012). doi:10.1117/12.925108

    Google Scholar 

  135. S. Seager, M. Kuchner, C.A. Hier-Majumder, B. Militzer, Mass-radius relationships for solid exoplanets. Astrophys. J. 669, 1279–1297 (2007). doi:10.1086/521346

    ADS  Google Scholar 

  136. S. Sigurdsson, Genesis of a planet in Messier 4. Astrophys. J. 415, 43–46 (1993). doi:10.1086/187028

    ADS  Google Scholar 

  137. F. Sohl, G. Schubert, T. Spohn, Geophysical constraints on the composition and structure of the Martian interior. J. Geophys. Res. 110, 12008 (2005). doi:10.1029/2005JE002520

    Google Scholar 

  138. J.F.P. Spronck, D.A. Fischer, Z.A. Kaplan, C. Schwab, Fiber scrambling for precise radial velocities at Lick and Keck observatories, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol. 8446 (2012). doi:10.1117/12.926289

    Google Scholar 

  139. T. Steinmetz, T. Wilken, C. Araujo-Hauck, R. Holzwarth, T.W. Hänsch, L. Pasquini, A. Manescau, S. D’Odorico, M.T. Murphy, T. Kentischer, W. Schmidt, T. Udem, Laser frequency combs for astronomical observations. Science 321, 1335 (2008). doi:10.1126/science.1161030

    ADS  Google Scholar 

  140. K.B. Stevenson, J. Harrington, N.B. Lust, N.K. Lewis, G. Montagnier, J.I. Moses, C. Visscher, J. Blecic, R.A. Hardy, P. Cubillos, C.J. Campo, Two nearby sub-Earth-sized exoplanet candidates in the GJ 436 system. Astrophys. J. 755, 9 (2012). doi:10.1088/0004-637X/755/1/9

    ADS  Google Scholar 

  141. P. Tenenbaum, J.L. Christiansen, J.M. Jenkins, J.F. Rowe, S. Seader, D.A. Caldwell, B.D. Clarke, J. Li, E.V. Quintana, J.C. Smith, M.C. Stumpe, S.E. Thompson, J.D. Twicken, J. Van Cleve, W.J. Borucki, M.T. Cote, M.R. Haas, D.T. Sanderfer, F.R. Girouard, T.C. Klaus, C.K. Middour, B. Wohler, N.M. Batalha, T. Barclay, J.E. Nickerson, Detection of potential transit signals in the first three quarters of Kepler mission data. Astrophys. J. Suppl. Ser. 199, 24 (2012). doi:10.1088/0067-0049/199/1/24

    ADS  Google Scholar 

  142. C. Terquem, J.C.B. Papaloizou, Migration and the formation of systems of hot super-Earths and Neptunes. Astrophys. J. 654, 1110–1120 (2007). doi:10.1086/509497

    ADS  Google Scholar 

  143. F. Tian, Thermal escape from super Earth atmospheres in the habitable zones of M stars. Astrophys. J. 703, 905–909 (2009). doi:10.1088/0004-637X/703/1/905

    ADS  Google Scholar 

  144. G. Torres, J. Andersen, A. Giménez, Accurate masses and radii of normal stars: modern results and applications. Astron. Astrophys. Rev. 18, 67–126 (2010). doi:10.1007/s00159-009-0025-1

    ADS  Google Scholar 

  145. C. Tully, R.E. Johnson, Low energy collisions between ground-state oxygen atoms. Planet. Space Sci. 49, 533–537 (2001). doi:10.1016/S0032-0633(01)00002-2

    ADS  Google Scholar 

  146. D. Valencia, D.D. Sasselov, R.J. O’Connell, Detailed models of super-Earths: how well can we infer bulk properties? Astrophys. J. 665, 1413–1420 (2007). doi:10.1086/519554

    ADS  Google Scholar 

  147. D. Valencia, M. Ikoma, T. Guillot, N. Nettelmann, Composition and fate of short-period super-Earths. The case of CoRoT-7b. Astron. Astrophys. 516, 20 (2010). doi:10.1051/0004-6361/200912839

    ADS  Google Scholar 

  148. J.A. Valenti, R.P. Butler, G.W. Marcy, Determining spectrometer instrumental profiles using FTS reference spectra. Publ. Astron. Soc. Pac. 107, 966 (1995). doi:10.1086/133645

    ADS  Google Scholar 

  149. L.M. van Haaften, G. Nelemans, R. Voss, P.G. Jonker, Formation of the planet around the millisecond pulsar J1719-1438. Astron. Astrophys. 541, 22 (2012). doi:10.1051/0004-6361/201218798

    ADS  Google Scholar 

  150. K.J. Walsh, A. Morbidelli, S.N. Raymond, D.P. O’Brien, A.M. Mandell, A low mass for Mars from Jupiter’s early gas-driven migration. Nature 475, 206–209 (2011). doi:10.1038/nature10201

    ADS  Google Scholar 

  151. W.R. Ward, Protoplanet migration by nebula tides. Icarus 126, 261–281 (1997). doi:10.1006/icar.1996.5647

    ADS  Google Scholar 

  152. S.J. Weidenschilling, Aerodynamics of solid bodies in the solar nebula. Mon. Not. R. Astron. Soc. 180, 57–70 (1977a)

    ADS  Google Scholar 

  153. S.J. Weidenschilling, The distribution of mass in the planetary system and solar nebula. Astrophys. Space Sci. 51, 153–158 (1977b). doi:10.1007/BF00642464

    ADS  Google Scholar 

  154. S.J. Weidenschilling, Iron/silicate fractionation and the origin of Mercury. Icarus 35, 99–111 (1978). doi:10.1016/0019-1035(78)90064-7

    ADS  Google Scholar 

  155. R. Weidling, C. Güttler, J. Blum, Free collisions in a microgravity many-particle experiment. I. Dust aggregate sticking at low velocities. Icarus 218, 688–700 (2012). doi:10.1016/j.icarus.2011.10.002

    ADS  Google Scholar 

  156. J.P. Williams, L.A. Cieza, Protoplanetary disks and their evolution. Annu. Rev. Astron. Astrophys. 49, 67–117 (2011). doi:10.1146/annurev-astro-081710-102548

    ADS  Google Scholar 

  157. A. Wolszczan, Confirmation of Earth-mass planets orbiting the millisecond pulsar PSR B1257+12. Science 264, 538–542 (1994). doi:10.1126/science.264.5158.538

    ADS  Google Scholar 

  158. A. Wolszczan, Discovery of pulsar planets. New Astron. Rev. 56, 2–8 (2012). doi:10.1016/j.newar.2011.06.002

    ADS  Google Scholar 

  159. J.T. Wright, B.S. Gaudi, Exoplanet detection methods, in Planets, Stars and Stellar Systems, ed. by T.D. Oswalt, L.M. French, P. Kalas (Springer, Berlin, 2013), p. 489. doi:10.1007/978-94-007-5606-9_10. ISBN 978-94-007-5605-2

    Google Scholar 

  160. J.T. Wright, S. Upadhyay, G.W. Marcy, D.A. Fischer, E.B. Ford, J.A. Johnson, Ten new and updated multiplanet systems and a survey of exoplanetary systems. Astrophys. J. 693, 1084–1099 (2009). doi:10.1088/0004-637X/693/2/1084

    ADS  Google Scholar 

  161. A.N. Youdin, S.J. Kenyon, in From Disks to Planets, ed. by T.D. Oswalt, L.M. French, P. Kalas (2013), p. 1. doi:10.1007/978-94-007-5606-9-1

    Google Scholar 

  162. J. Zendejas, A. Segura, A.C. Raga, Atmospheric mass loss by stellar wind from planets around main sequence M stars. Icarus 210, 539–544 (2010). doi:10.1016/j.icarus.2010.07.013

    ADS  Google Scholar 

  163. J.-L. Zhou, S.J. Aarseth, D.N.C. Lin, M. Nagasawa, Origin and ubiquity of short-period Earth-like planets: evidence for the sequential accretion theory of planet formation. Astrophys. J. 631, 85–88 (2005). doi:10.1086/497094

    ADS  Google Scholar 

  164. A. Zsom, C.W. Ormel, C. Güttler, J. Blum, C.P. Dullemond, The outcome of protoplanetary dust growth: pebbles, boulders, or planetesimals? II. Introducing the bouncing barrier. Astron. Astrophys. 513, 57 (2010). doi:10.1051/0004-6361/200912976

    ADS  Google Scholar 

Download references

Acknowledgements

This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX09AF08G and by other grants and contracts. This paper includes data collected by the Kepler mission. Funding for the Kepler mission is provided by the NASA Science Mission directorate. EG acknowledges support from NASA grants NNX10AI90G and NNX11AC33G. We thank Y. Kokubo for providing Fig. 5, E. Kite for commenting on an earlier version of this manuscript and E. Petigura and A. Howard for helpful discussions.

Author information

Affiliations

Authors

Corresponding author

Correspondence to E. Gaidos.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Sinukoff, E., Fulton, B., Scuderi, L. et al. Below One Earth: The Detection, Formation, and Properties of Subterrestrial Worlds. Space Sci Rev 180, 71–99 (2013). https://doi.org/10.1007/s11214-013-0019-1

Download citation

Keywords

  • Exoplanets
  • Kepler mission
  • Planet formation
  • Astrobiology