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A method to identify the boundary between rocky and gaseous exoplanets from tidal theory and transit durations

Published online by Cambridge University Press:  06 March 2014

Rory Barnes
Rory Barnes*
Affiliation:
Astronomy Department, University of Washington, Box 951580, Seattle, WA 98195, USA NASA Astrobiology Institute – Virtual Planetary Laboratory Lead Team, USA e-mail: [email protected]
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Abstract

The determination of an exoplanet as rocky is critical for the assessment of planetary habitability. Observationally, the number of small-radius, transiting planets with accompanying mass measurements is insufficient for a robust determination of the transitional mass or radius. Theoretically, models predict that rocky planets can grow large enough to become gas giants when they reach ~10 MEarth, but the transitional mass remains unknown. Here I show how transit data, interpreted in the context of tidal theory, can reveal the critical radius that separates rocky and gaseous exoplanets. Standard tidal models predict that rocky exoplanets’ orbits are tidally circularized much more rapidly than gaseous bodies’, suggesting the former will tend to be found on circular orbits at larger semi-major axes than the latter. Well-sampled transits can provide a minimum eccentricity of the orbit, allowing a measurement of this differential circularization. I show that this effect should be present in the data from the Kepler spacecraft, but is not apparent. Instead, it appears that there is no evidence of tidal circularization at any planetary radius, probably because the publicly-available data, particularly the impact parameters, are not accurate enough. I also review the bias in the transit duration towards values that are smaller than that of planets on circular orbits, stressing that the azimuthal velocity of the planet determines the transit duration. The ensemble of Kepler planet candidates may be able to determine the critical radius between rocky and gaseous exoplanets, tidal dissipation as a function of planetary radius, and discriminate between tidal models.

Keywords

ExoplanetsTidal TheoryTransits
Type
Research Article
Information
International Journal of Astrobiology , Volume 14 , Issue 2: SPECIAL ISSUE: EXOPLANET , April 2015 , pp. 321 - 333
Copyright
Copyright © Cambridge University Press 2014 

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References

Agol, E., Steffen, J., Sari, R. & Clarkson, W. (2005). Mon. Not. R. Astron. Soc. 359, 567.CrossRefGoogle Scholar
Anglada-Escudé, G. et al. (2012). Astrophys. J. 751, L16.CrossRefGoogle Scholar
Anglada-Escudé, G. et al. (2013). Astron. Astrophys. 556, A126.CrossRefGoogle Scholar
Barnes, J.W. (2007). PASP 119, 986.CrossRefGoogle Scholar
Barnes, R. et al. (2013). Astrobiology 13, 225.CrossRefGoogle Scholar
Batalha, N.M. et al. (2011). Astrophys. J. 729, 27.CrossRefGoogle Scholar
Batalha, N.M. et al. (2013). Astrophys. J. Suppl. 204, 24.CrossRefGoogle Scholar
Bodenheimer, P., Lin, D.N.C. & Mardling, R.A. (2001). Astrophys. J. 548, 466.CrossRefGoogle Scholar
Bolmont, E. et al. (2013). Astron. Astrophys. 556, A17.Google Scholar
Bonfils, X. et al. (2013). Astron. Astrophys. 549, A109.CrossRefGoogle Scholar
Borucki, W.J. & Summers, A.L. (1984). Icarus 58, 121.CrossRefGoogle Scholar
Boyajian, T.S. et al. (2012). Astrophys. J. 757, 112.CrossRefGoogle Scholar
Burke, C.J. (2008). Astrophys. J. 679, 1566.CrossRefGoogle Scholar
Butler, R.P. et al. (2006). Astrophys. J. 646, 505.CrossRefGoogle Scholar
Darwin, G.H. (1880). R. Soc. Lond. Phil. Trans. Ser. I 171, 713.Google Scholar
Dawson, R.I. & Johnson, J.A. (2012). Astrophys. J. 756, 122.CrossRefGoogle Scholar
Dole, S.H. (1964). Habitable planets for man.Google Scholar
Dressing, C.D. & Charbonneau, D. (2013). Astrophys. J. 767, 95.CrossRefGoogle Scholar
Efroimsky, M. & Williams, J.G. (2009). Celes. Mech. Dyn. Astron. 104, 257.CrossRefGoogle Scholar
Everett, M.E., Howell, S.B., Silva, D.R. & Szkody, P. (2013). Astrophys. J. 771, 107.CrossRefGoogle Scholar
Ferraz-Mello, S., Rodríguez, A. & Hussmann, H. (2008). Celes. Mech. Dyn. Astron. 101, 171.CrossRefGoogle Scholar
Ferraz-Mello, S., Tadeu Dos Santos, M., Beaugé, C., Michtchenko, T.A. & Rodríguez, A. (2011). Astron. Astrophys. 531, A161.CrossRefGoogle Scholar
Ford, E.B., Quinn, S.N. & Veras, D. (2008). Astrophys. J. 678, 1407.CrossRefGoogle Scholar
Goldreich, P. & Soter, S. (1966). Icarus 5, 375.CrossRefGoogle Scholar
Greenberg, R. (2009). Astrophys. J. 698, L42.CrossRefGoogle Scholar
Guillot, T. (2005). Annu. Rev. Earth Planet. Sci. 33, 493.CrossRefGoogle Scholar
Heller, R., Leconte, J. & Barnes, R. (2011). Astron. Astrophys. 528, A27+.CrossRefGoogle Scholar
Henning, W.G., O'Connell, R.J. & Sasselov, D.D. (2009). Astrophys. J. 707, 1000.CrossRefGoogle Scholar
Holman, M.J. & Murray, N.W. (2005). Science 307, 1288.CrossRefGoogle Scholar
Holman, M.J. et al. (2010). Science 330, 51.CrossRefGoogle Scholar
Hubickyj, O., Bodenheimer, P. & Lissauer, J.J. (2005). Icarus 179, 415.CrossRefGoogle Scholar
Hut, P. (1981). Astron. Astrophys. 99, 126.Google Scholar
Ibgui, L. & Burrows, A. (2009). Astrophys. J. 700, 1921.CrossRefGoogle Scholar
Ikoma, M., Emori, H. & Nakazawa, K. (2001). Astrophys. J. 553, 999.CrossRefGoogle Scholar
Jackson, B., Barnes, R. & Greenberg, R. (2008a). Mon. Not. R. Astron. Soc. 391, 237.CrossRefGoogle Scholar
Jackson, B., Greenberg, R. & Barnes, R. (2008b). Astrophys. J. 678, 1396.CrossRefGoogle Scholar
Jackson, B., Greenberg, R. & Barnes, R. (2008c). Astrophys. J. 681, 1631.CrossRefGoogle Scholar
Jackson, B., Barnes, R. & Greenberg, R. (2009). Astrophys. J. 698, 1357.CrossRefGoogle Scholar
Jackson, B. et al. (2010). Mon. Not. R. Astron. Soc. 407, 910.CrossRefGoogle Scholar
Jackson, B. et al. (2013). Astrophys. J. 779, 165.Google Scholar
Kane, S.R., Ciardi, D.R., Gelino, D.M. & von Braun, K. (2012). Astrophys. J. 425, 757.Google Scholar
Kasting, J.F., Whitmire, D.P. & Reynolds, R.T. (1993). Icarus 101, 108.CrossRefGoogle Scholar
Kipping, D.M. (2010). Mon. Not. R. Astron. Soc. 407, 301.CrossRefGoogle Scholar
Kopparapu, R.K. et al. (2013). Astrophys. J. 765, 131.CrossRefGoogle Scholar
Lainey, V. et al. (2012). Astrophys. J. 752, 14.CrossRefGoogle Scholar
Lambeck, K. (1977). R. Soc. Lond. Phil. Trans. Ser. A 287, 545.Google Scholar
Leconte, J., Chabrier, G., Baraffe, I. & Levrard, B. (2010). Astron. Astrophys. 516, A64+.CrossRefGoogle Scholar
Léger, A. et al. (2009). Astron. Astrophys. 506, 287.CrossRefGoogle Scholar
Leitzinger, M. et al. (2011). Planet. Space Sci. 59, 1472.CrossRefGoogle Scholar
Levrard, B., Winisdoerffer, C. & Chabrier, G. (2009). Astrophys. J. 692, L9.CrossRefGoogle Scholar
Lissauer, J.J., Hubickyj, O., D'Angelo, G. & Bodenheimer, P. (2009). Icarus 199, 338.CrossRefGoogle Scholar
Lissauer, J.J. et al. (2011). Nature 470, 53.CrossRefGoogle Scholar
Lissauer, J.J. et al. (2013). Astrophys. J. 770, 131.CrossRefGoogle Scholar
Lopez, E.D., Fortney, J.J. & Miller, N. (2012). Astrophys. J. 761, 59.CrossRefGoogle Scholar
Makarov, V.V. & Efroimsky, M. (2013). Astrophys. J. 764, 27.CrossRefGoogle Scholar
Mandel, K. & Agol, E. (2002). Astrophys. J. 580, L171.CrossRefGoogle Scholar
Mardling, R.A. & Lin, D.N.C. (2002). Astrophys. J. 573, 829.CrossRefGoogle Scholar
Mayor, M. et al. (2009). Astron. Astrophys. 507, 487.CrossRefGoogle Scholar
Militzer, B., Hubbard, W.B., Vorberger, J., Tamblyn, I. & Bonev, S.A. (2008). Astrophys. J. 688, L45.CrossRefGoogle Scholar
Moorhead, A.V. et al. (2011). Astrophys. J. Suppl. 197, 1.CrossRefGoogle Scholar
Movshovitz, N., Bodenheimer, P., Podolak, M. & Lissauer, J.J. (2010). Icarus 209, 616.CrossRefGoogle Scholar
Ogilvie, G.I. & Lin, D.N.C. (2004). Astrophys. J. 610, 477.CrossRefGoogle Scholar
Owen, J.E. & Wu, Y. (2013). Astrophys. J. 775, 105.CrossRefGoogle Scholar
Plavchan, P. et al. (2013). PASP, in press.Google Scholar
Pollack, J.B. et al. (1996). Icarus 124, 62.CrossRefGoogle Scholar
Poppenhaeger, K. et al. (2012). Astron. Astrophys. 541, A26.CrossRefGoogle Scholar
Queloz, D. et al. (2009). Astron. Astrophys. 506, 303.CrossRefGoogle Scholar
Rasio, F.A., Tout, C.A., Lubow, S.H. & Livio, M. (1996). Astrophys. J. 470, 1187.Google Scholar
Ribas, I., Guinan, E.F., Güdel, M. & Audard, M. (2005). Astrophys. J. 622, 680.CrossRefGoogle Scholar
Selsis, F. et al. (2007). Astron. Astrophys. 476, 1373.CrossRefGoogle Scholar
Socrates, A., Katz, B., Dong, S. & Tremaine, S. (2012). Astrophys. J. 750, 106.CrossRefGoogle Scholar
Sotin, C., Grasset, O. & Mocquet, A. (2007). Icarus 191, 337.CrossRefGoogle Scholar
Storch, N. & Lai, D. (2013). Mon. Not. Roy. Astron. Soc., in press.Google Scholar
Tingley, B. & Sackett, P.D. (2005). Astrophys. J. 627, 1011.CrossRefGoogle Scholar
Torres, G., Andersen, J. & Giménez, A. (2010). Astron. Astrophys. 18, 67.Google Scholar
Udry, S. et al. (2007). Astron. Astrophys. Rev. 469, L43.CrossRefGoogle Scholar
Valencia, D., Ikoma, M., Guillot, T. & Nettelmann, N. (2010). Astro. Astrophys. 516, A20.CrossRefGoogle Scholar
Vogt, S.S. et al. (2010). Astrophys. J. 723, 954.CrossRefGoogle Scholar
von Braun, K. et al. (2011). Astrophys. J. 729, L26.CrossRefGoogle Scholar
Wisdom, J. (2008). Icarus 193, 637.CrossRefGoogle Scholar
Yoder, C.F. (1995). Astrometric and Geodetic Properties of Earth and the Solar System. In Global Earth Physics: A Handbook of Physical Constants, ed. Ahrens, T.J., pp. 1–31.Google Scholar
Zhang, K. & Hamilton, D.P. (2008). T. J. Icarus 193, 267.CrossRefGoogle Scholar