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Formation of Super-Earths

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Handbook of Exoplanets

Abstract

Super-Earths are the most abundant planets known to date and are characterized by having sizes between that of Earth and Neptune, typical orbital periods of less than 100 days, and gaseous envelopes that are often massive enough to significantly contribute to the planet’s overall radius. Furthermore, super-Earths regularly appear in tightly packed multiple-planet systems, but resonant configurations in such systems are rare. This chapter summarizes current super-Earth formation theories. It starts from the formation of rocky cores and subsequent accretion of gaseous envelopes. We follow the thermal evolution of newly formed super-Earths and discuss their atmospheric mass loss due to disk dispersal, photoevaporation, core-cooling, and collisions. We conclude with a comparison of observations and theoretical predictions, highlighting that even super-Earths that appear as barren rocky cores today likely formed with primordial hydrogen and helium envelopes and discuss some paths forward for the future.

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References

  • Allard F, Hauschildt PH, Alexander DR, Tamanai A, Schweitzer A (2001) The limiting effects of dust in brown dwarf model atmospheres. ApJ 556:357–372

    Article  ADS  Google Scholar 

  • Armitage PJ (2013) Astrophysics of planet formation. Cambridge University Press, Cambridge/New York

    Google Scholar 

  • Batalha NM, Rowe JF, Bryson ST et al (2013) Planetary candidates observed by Kepler. III. Analysis of the first 16 months of data. ApJS 204:24

    Google Scholar 

  • Batygin K (2015) Capture of planets into mean-motion resonances and the origins of extrasolar orbital architectures. MNRAS 451:2589–2609

    Google Scholar 

  • Borucki WJ, Koch D, Basri G et al (2010) Kepler planet-detection mission: introduction and first results. Science 327:977

    Google Scholar 

  • Carter JA, Agol E, Chaplin WJ et al (2012) Kepler-36: a pair of planets with neighboring orbits and dissimilar densities. Science 337:556

    Google Scholar 

  • Chen H, Rogers LA (2016) Evolutionary analysis of gaseous sub-Neptune-mass planets with MESA. ApJ 831:180

    Article  ADS  Google Scholar 

  • D’Angelo G, Bodenheimer P (2013) Three-dimensional radiation-hydrodynamics calculations of the envelopes of young planets embedded in protoplanetary disks. ApJ 778:77

    Article  ADS  Google Scholar 

  • Dawson RI, Lee EJ, Chiang E (2016) Correlations between compositions and orbits established by the giant impact era of planet formation. ApJ 822:54

    Article  ADS  Google Scholar 

  • Deck KM, Batygin K (2015) Migration of two massive planets into (and out of) first order mean motion resonances. ApJ 810:119

    Article  ADS  Google Scholar 

  • Fabrycky DC, Lissauer JJ, Ragozzine D et al (2014) Architecture of Kepler’s multi-transiting systems. II. New investigations with twice as many candidates. ApJ 790:146

    Article  ADS  Google Scholar 

  • Freedman RS, Marley MS, Lodders K (2008) Line and mean opacities for ultracool dwarfs and extrasolar planets. ApJS 174:504–513

    Google Scholar 

  • Fressin F, Torres G, Charbonneau D et al (2013) The false positive rate of Kepler and the occurrence of planets. ApJ 766:81

    Article  ADS  Google Scholar 

  • Fulton BJ, Petigura EA, Howard AW et al (2017) The California-Kepler survey. III. A gap in the radius distribution of small planets. ArXiv e-prints

    Article  ADS  Google Scholar 

  • Fung J, Artymowicz P, Wu Y (2015) The 3D flow field around an embedded planet. ApJ 811:101

    Article  ADS  Google Scholar 

  • Ginzburg S, Sari R (2017) Tidal heating of young super-Earth atmospheres. MNRAS 464:3937–3944

    Article  ADS  Google Scholar 

  • Ginzburg S, Schlichting HE, Sari R (2016) Super-Earth atmospheres: self-consistent gas accretion and retention. ApJ 825:29

    Article  ADS  Google Scholar 

  • Ginzburg S, Schlichting HE, Sari R (2017) Core-powered mass loss sculpts the radius distribution of small exoplanets. ArXiv e-prints

    Google Scholar 

  • Goldreich P, Schlichting HE (2014) Overstable librations can account for the paucity of mean motion resonances among exoplanet pairs. AJ 147:32

    Article  ADS  Google Scholar 

  • Greenzweig Y, Lissauer JJ (1990) Accretion rates of protoplanets. Icarus 87:40–77

    Article  ADS  Google Scholar 

  • Hansen BMS, Murray N (2012) Migration then assembly: formation of Neptune-mass planets inside 1 AU. ApJ 751:158

    Article  ADS  Google Scholar 

  • Hayashi C (1981) 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

    Google Scholar 

  • Howard AW, Marcy GW, Bryson ST et al (2012) Planet occurrence within 0.25 AU of solar-type stars from Kepler. ApJS 201:15

    Google Scholar 

  • Hwang J, Chatterjee S, Lombardi J Jr, Steffen J, Rasio F (2017) Hydrodynamics of collisions between sub-Neptunes. ArXiv e-prints

    Google Scholar 

  • Ikoma M, Hori Y (2012) In situ accretion of hydrogen-rich atmospheres on short-period super-Earths: implications for the Kepler-11 planets. ApJ 753:66

    Article  ADS  Google Scholar 

  • Inamdar NK, Schlichting HE (2015) The formation of super-Earths and mini-Neptunes with giant impacts. MNRAS 448:1751–1760

    Article  ADS  Google Scholar 

  • Inamdar NK, Schlichting HE (2016) Stealing the gas: giant impacts and the large diversity in exoplanet densities. ApJ 817:L13

    Article  ADS  Google Scholar 

  • Izidoro A, Raymond SN, Morbidelli A, Hersant F, Pierens A (2015) Gas giant planets as dynamical barriers to inward-migrating super-Earths. ApJ 800:L22

    Google Scholar 

  • Izidoro A, Ogihara M, Raymond SN et al (2017) Breaking the chains: hot super-Earth systems from migration and disruption of compact resonant chains. ArXiv e-prints

    Article  ADS  Google Scholar 

  • Jin S, Mordasini C, Parmentier V et al (2014) Planetary population synthesis coupled with atmospheric escape: a statistical view of evaporation. ApJ 795:65

    Article  ADS  Google Scholar 

  • Lee EJ, Chiang E (2015) To cool is to accrete: analytic scalings for nebular accretion of planetary atmospheres. ApJ 811:41

    Google Scholar 

  • Lee EJ, Chiang E (2016) Breeding super-Earths and birthing super-puffs in transitional disks. ApJ 817:90

    Google Scholar 

  • Lehmer OR, Catling DC (2017) Rocky worlds limited to 1.8 Earth radii by atmospheric escape during a stars extreme UV saturation. Astrophys J 845(2):130. http://stacks.iop.org/0004-637X/845/i=2/a=130

    Article  ADS  Google Scholar 

  • Liu SF, Hori Y, Lin DNC, Asphaug E (2015) Giant impact: an efficient mechanism for the devolatilization of super-Earths. ApJ 812:164

    Google Scholar 

  • Lopez ED, Fortney JJ (2013) The role of core mass in controlling evaporation: the Kepler radius distribution and the Kepler-36 density dichotomy. ApJ 776:2

    Article  ADS  Google Scholar 

  • Lopez ED, Fortney JJ (2014) Understanding the mass-radius relation for sub-Neptunes: radius as a proxy for composition. ApJ 792:1

    Article  ADS  Google Scholar 

  • Lopez ED, Fortney JJ, Miller N (2012) How thermal evolution and mass-loss sculpt populations of super-Earths and sub-Neptunes: application to the Kepler-11 system and beyond. ApJ 761:59

    Article  ADS  Google Scholar 

  • Marcy GW, Butler RP, Fischer D et al (2001) A pair of resonant planets orbiting GJ 876. ApJ 556:296–301

    Article  ADS  Google Scholar 

  • Marcy GW, Isaacson H, Howard AW et al (2014) Masses, radii, and orbits of small Kepler planets: the transition from gaseous to rocky planets. ApJS 210:20

    Google Scholar 

  • Mills SM, Fabrycky DC, Migaszewski C et al (2016) A resonant chain of four transiting, sub-Neptune planets. Nature 533:509–512

    Google Scholar 

  • Najita JR, Kenyon SJ (2014) The mass budget of planet-forming discs: isolating the epoch of planetesimal formation. MNRAS 445:3315–3329

    Google Scholar 

  • Ormel CW, Kuiper R, Shi JM (2015a) Hydrodynamics of embedded planets’ first atmospheres – I. A centrifugal growth barrier for 2D flows. MNRAS 446:1026–1040

    Article  ADS  Google Scholar 

  • Ormel CW, Shi JM, Kuiper R (2015b) Hydrodynamics of embedded planets’ first atmospheres – II. A rapid recycling of atmospheric gas. MNRAS 447:3512–3525

    Article  ADS  Google Scholar 

  • Owen JE, Alvarez MA (2016) UV driven evaporation of close-in planets: energy-limited, recombination-limited, and photon-limited flows. ApJ 816:34

    Google Scholar 

  • Owen JE, Jackson AP (2012) Planetary evaporation by UV & X-ray radiation: basic hydrodynamics. MNRAS 425:2931–2947

    Google Scholar 

  • Owen JE, Wu Y (2013) Kepler planets: a tale of evaporation. ApJ 775:105

    Article  ADS  Google Scholar 

  • Owen JE, Wu Y (2016) Atmospheres of low-mass planets: the “Boil-off”. ApJ 817:107

    Google Scholar 

  • Pan M, Schlichting HE (2017) Avoiding resonance capture in multi-planet extrasolar systems. ArXiv e-prints

    Google Scholar 

  • Powell D, Murray-Clay R, Schlichting HE (2017) Using ice and dust lines to constrain the surface densities of protoplanetary disks. ApJ 840:93

    Article  ADS  Google Scholar 

  • Rafikov RR (2006) Atmospheres of protoplanetary cores: critical mass for nucleated instability. ApJ 648:666–682.

    Article  ADS  Google Scholar 

  • Raymond SN, Barnes R, Mandell AM (2008) Observable consequences of planet formation models in systems with close-in terrestrial planets. MNRAS 384:663–674

    Article  ADS  Google Scholar 

  • Rein H (2012) Period ratios in multiplanetary systems discovered by Kepler are consistent with planet migration. MNRAS 427:L21–L24

    ADS  Google Scholar 

  • Rogers LA (2015) Most 1.6 Earth-radius planets are not rocky. ApJ 801:41

    Article  ADS  Google Scholar 

  • Schlichting HE (2014) Formation of close in super-Earths and mini-Neptunes: required disk masses and their implications. ApJ 795:L15

    Article  ADS  Google Scholar 

  • Seager S, Kuchner M, Hier-Majumder CA, Militzer B (2007) Mass-radius relationships for solid exoplanets. ApJ 669:1279–1297

    Article  ADS  Google Scholar 

  • Steffen JH, Fabrycky DC, Agol E et al (2013) Transit timing observations from Kepler – VII. Confirmation of 27 planets in 13 multiplanet systems via transit timing variations and orbital stability. MNRAS 428:1077–1087

    Article  ADS  Google Scholar 

  • Tu L, Johnstone CP, Güdel M, Lammer H (2015) The extreme ultraviolet and X-ray sun in time: high-energy evolutionary tracks of a solar-like star. A&A 577:L3

    Article  ADS  Google Scholar 

  • van Boekel R, Henning T, Menu J et al (2017) Three radial gaps in the disk of TW Hydrae imaged with SPHERE. ApJ 837:132

    Article  ADS  Google Scholar 

  • Weiss LM, Marcy GW (2014) The mass-radius relation for 65 exoplanets smaller than 4 Earth radii. ApJ 783:L6

    Article  ADS  Google Scholar 

  • Weiss LM, Marcy GW, Petigura EA et al (2017) The California-Kepler survey V. Peas in a pod: planets in a Kepler multi-planet system are similar in size and regularly spaced. ArXiv e-prints

    Google Scholar 

  • Wolfgang A, Lopez E (2015) How rocky are they? The composition distribution of Kepler’s sub-Neptune planet candidates within 0.15 AU. ApJ 806:183

    Article  ADS  Google Scholar 

  • Wu Y, Lithwick Y (2013) Density and eccentricity of Kepler planets. ApJ 772:74

    Article  ADS  Google Scholar 

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Author information

Authors and Affiliations

  1. University of California, Los Angeles, CA, USA

    Hilke E. Schlichting

  2. Massachusetts Institute of Technology, Cambridge, MA, USA

    Hilke E. Schlichting

Authors
  1. Hilke E. Schlichting
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Correspondence to Hilke E. Schlichting .

Editor information

Editors and Affiliations

  1. Instituto de Astrofísica de Canarias , La Laguna, Spain

    Hans J. Deeg

  2. Instituto de Astrofísica de Canarias, La Laguna, Spain

    Juan Antonio Belmonte

Section Editor information

  1. Origins Institute, McMaster University, Hamilton, Canada

    Ralph Pudritz

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Schlichting, H.E. (2018). Formation of Super-Earths. In: Deeg, H., Belmonte, J. (eds) Handbook of Exoplanets . Springer, Cham. https://doi.org/10.1007/978-3-319-30648-3_141-1

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  • DOI: https://doi.org/10.1007/978-3-319-30648-3_141-1

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  • Publisher Name: Springer, Cham

  • Print ISBN: 978-3-319-30648-3

  • Online ISBN: 978-3-319-30648-3

  • eBook Packages: Springer Reference Physics and AstronomyReference Module Physical and Materials ScienceReference Module Chemistry, Materials and Physics

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