Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Continuous reorientation of synchronous terrestrial planets due to mantle convection

Abstract

Many known rocky exoplanets are thought to have been spun down by tidal interactions to a state of synchronous rotation, in which a planet’s period of rotation is equal to that of its orbit around its host star. Investigations into atmospheric and surface processes occurring on such exoplanets thus commonly assume that day and night sides are fixed with respect to the surface over geological timescales. Here we use an analytical model to show that true polar wander—where a planetary body’s spin axis shifts relative to its surface because of changes in mass distribution—can continuously reorient a synchronous rocky exoplanet. As occurs on Earth, we find that even weak mantle convection in a rocky exoplanet can produce density heterogeneities within the mantle sufficient to reorient the planet. Moreover, we show that this reorientation is made very efficient by the slower rotation rate of a synchronous planet when compared with Earth, which limits the stabilizing effect of rotational and tidal deformations. Furthermore, a relatively weak lithosphere limits its ability to support remnant loads and stabilize against reorientation. Although uncertainties exist regarding the mantle and lithospheric evolution of these worlds, we suggest that the axes of smallest and largest moment of inertia of synchronous exoplanets with active mantle convection change continuously over time, but remain closely aligned with the star–planet and orbital axes, respectively.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Fig. 1: Schematic representation of TPW driven by mantle convection on a synchronous planet.
Fig. 2: XTPW on known rocky exoplanets as a function of their orbital period (dots).
Fig. 3: Minimal inertia anomaly (〈\(\widehat {\mathscr C}\)min/\({\mathscr I}\)s) needed to excite significant polar wander as a function of the planetary temperature (TBB).
Fig. 4: Dimensionless contribution of the elastic remnant bulge to the inertia deformation tensor as a function of the planet radius for all known rocky exoplanets (〈\(\hat{\mathscr{C}}\)lit/\(\mathscr{I}\)I; Methods).

References

  1. 1.

    Dole, S. H. Habitable Planets for Man 1st edn (Blaisdell Pub. Co., New York, 1964).

  2. 2.

    Leconte, J. et al. 3D climate modeling of close-in land planets: circulation patterns, climate moist bistability, and habitability. Astron. Astrophys.554, A69 (2013).

    Article  Google Scholar 

  3. 3.

    Menou, K. Water-trapped worlds. Astrophys. J.774, 51 (2013).

    Article  Google Scholar 

  4. 4.

    Turbet, M. et al. The habitability of Proxima Centauri b. II. Possible climates and observability. Astron. Astrophys.596, A112 (2016).

    Article  Google Scholar 

  5. 5.

    Wordsworth, R. Atmospheric heat redistribution and collapse on tidally locked rocky planets. Astrophys. J.806, 180 (2015).

    Article  Google Scholar 

  6. 6.

    Turbet, M., Forget, F., Leconte, J., Charnay, B. & Tobie, G. CO2 condensation is a serious limit to the deglaciation of Earth-like planets. Earth. Planet. Sci. Lett.476, 11–21 (2017).

    Article  Google Scholar 

  7. 7.

    Haberle, R. M., McKay, C. P., Tyler, D. & Reynolds, R. T. Can synchronously rotating planets support an atmosphere? In Circumstellar Habit. Zones: Proc. 1st Int. Conf (ed. Doyle, L. R.) 29 (Travis House, CA, 1996).

  8. 8.

    Heng, K. & Kopparla, P. On the stability of super-Earth atmospheres. Astrophys. J.754, 60 (2012).

    Article  Google Scholar 

  9. 9.

    Walker, J. C. G., Hays, P. B. & Kasting, J. F. A negative feedback mechanism for the long-term stabilization of the earth’s surface temperature. J. Geophys. Res.86, 9776–9782 (1981).

    Article  Google Scholar 

  10. 10.

    Edson, A. R., Kasting, J. F., Pollard, D., Lee, S. & Bannon, P. R. The carbonate–silicate cycle and CO2/climate feedbacks on tidally locked terrestrial lanets. Astrobiology12, 562–571 (2012).

    Article  Google Scholar 

  11. 11.

    Kite, E. S., Gaidos, E. & Manga, M. Climate instability on tidally locked exoplanets. Astrophys. J.743, 41 (2011).

    Article  Google Scholar 

  12. 12.

    Makarov, V. V., Berghea, C. & Efroimsky, M. Dynamical evolution and spin–orbit resonances of potentially hbitable exoplanets: the case of GJ 581d. Astrophys. J.761, 83 (2012).

    Article  Google Scholar 

  13. 13.

    Leconte, J., Wu, H., Menou, K. & Murray, N. Asynchronous rotation of Earth-mass planets in the habitable zone of lower-mass stars.Science347, 632–635 (2015).

    Article  Google Scholar 

  14. 14.

    Munk, W. H. & MacDonald, G. J. F. The Rotation of the Earth: A Geophysical Discussion (Cambridge University Press, New York, 1960).

  15. 15.

    Evans, D. A. D. True polar wander and supercontinents. Tectonophysics362, 303–320 (2003).

    Article  Google Scholar 

  16. 16.

    Matsuyama, I., Nimmo, F. & Mitrovica, J. X. Planetary reorientation. Annu. Rev. Earth. Planet. Sci.42, 605–634 (2014).

    Article  Google Scholar 

  17. 17.

    Neron de Surgy, O. & Laskar, J. On the long term evolution of the spin of the Earth. Astron. Astrophys.318, 975–989 (1997).

    Google Scholar 

  18. 18.

    Goldstein, H., Poole, C. & Safko, J. Classical Mechanics (Addison-Wesley, San Francisco, 2002).

    Google Scholar 

  19. 19.

    Gold, T. Instability of the Earth’s axis of rotation. Nature175, 526–529 (1955).

    Article  Google Scholar 

  20. 20.

    Matsuyama, I. & Nimmo, F. Rotational stability of tidally deformed planetary bodies. J. Geophys. Res. Planets112, E11003 (2007).

    Article  Google Scholar 

  21. 21.

    Tsai, V. C. & Stevenson, D. J. Theoretical constraints on true polar wander. J. Geophys. Res. Solid Earth112, B05415 (2007).

    Article  Google Scholar 

  22. 22.

    Hager, B. H., Clayton, R. W., Richards, M. A., Comer, R. P. & Dziewonski, A. M. Lower mantle heterogeneity, dynamic topography and the geoid.Nature313, 541–545 (1985).

    Article  Google Scholar 

  23. 23.

    Zhong, S., Zhang, N., Li, Z.-X. & Roberts, J. H. Supercontinent cycles, true polar wander, and very long-wavelength mantle convection. Earth. Planet. Sci. Lett.261, 551–564 (2007).

    Article  Google Scholar 

  24. 24.

    Gurnis, M. Large-scale mantle convection and the aggregation and dispersal of supercontinents. Nature332, 695–699 (1988).

    Article  Google Scholar 

  25. 25.

    Rogers, L. A. Most 1.6 Earth-radius planets are not rocky.Astrophys. J.801, 41 (2015).

    Article  Google Scholar 

  26. 26.

    Willemann, R. J. Reorientation of planets with elastic lithospheres. Icarus60, 701–709 (1984).

    Article  Google Scholar 

  27. 27.

    Daradich, A. et al. Equilibrium rotational stability and figure of Mars. Icarus194, 463–475 (2008).

    Article  Google Scholar 

  28. 28.

    Turcotte, D. L., Willemann, R. J., Haxby, W. F. & Norberry, J. Role of membrane stresses in the support of planetary topography. J. Geophys. Res.86, 3951–3959 (1981).

    Article  Google Scholar 

  29. 29.

    Willemann, R. J. & Turcotte, D. L. Support of topographic and other loads on the moon and on the terrestrial planets. In Lunar Planet. Sci. Conf. Proc. Vol. 12 (eds Merrill, R. B. & Ridings, R.) 837–851 (Pergamon, New York, 1982).

  30. 30.

    Monin, A. S. Planetary evolution and global tectonics. Tectonophysics199, 149–164 (1991).

    Article  Google Scholar 

  31. 31.

    Fortney, J. J., Marley, M. S. & Barnes, J. W. Planetary radii across five orders of magnitude in mass and stellar insolation: application to transits. Astrophys. J.659, 1661–1672 (2007).

    Article  Google Scholar 

  32. 32.

    Goldreich, P. & Soter, S. Q in the solar system. Icarus5, 375–389 (1966).

    Article  Google Scholar 

  33. 33.

    Mitrovica, J. X. & Forte, A. M. A new inference of mantle viscosity based upon joint inversion of convection and glacial isostatic adjustment data. Earth. Planet. Sci. Lett.225, 177–189 (2004).

    Article  Google Scholar 

  34. 34.

    Post, R. L. Jr. & Griggs, D. T. The Earth’s mantle: evidence of non-Newtonian flow. Science181, 1242–1244 (1973).

    Article  Google Scholar 

  35. 35.

    Spada, G., Sabadini, R. & Boschi, E. Long-term rotation and mantle dynamics of the Earth, Mars, and Venus. J. Geophys. Res.101, 2253–2266 (1996).

    Article  Google Scholar 

  36. 36.

    Sohl, F. & Spohn, T. The interior structure of Mars: implications from SNC meteorites. J. Geophys. Res.102, 1613–1636 (1997).

    Article  Google Scholar 

  37. 37.

    Moore, W. B., Simon, J. I. & Webb, A. A. G. Heat-pipe planets.Earth. Planet. Sci. Lett.474, 13–19 (2017).

    Article  Google Scholar 

  38. 38.

    Kankanamge, D. G. J. & Moore, W. B. Heat transport in the Hadean mantle: from heat pipes to plates. Geophys. Res. Lett.43, 3208–3214 (2016).

    Article  Google Scholar 

Download references

Acknowledgements

This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 679030/WHIPLASH). The author thanks E. Couderc, R. Jolivet, L. Londeix and F. Selsis for comments on the initial manuscript.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Jérémy Leconte.

Ethics declarations

Competing interests

The author declares no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary figure and table

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Leconte, J. Continuous reorientation of synchronous terrestrial planets due to mantle convection. Nature Geosci 11, 168–172 (2018). https://doi.org/10.1038/s41561-018-0071-2

Download citation

Further reading

  • Ariel planetary interiors White Paper

    • Ravit Helled
    • , Stephanie Werner
    • , Caroline Dorn
    • , Tristan Guillot
    • , Masahiro Ikoma
    • , Yuichi Ito
    • , Mihkel Kama
    • , Tim Lichtenberg
    • , Yamila Miguel
    • , Oliver Shorttle
    • , Paul J. Tackley
    • , Diana Valencia
    •  & Allona Vazan

    Experimental Astronomy (2021)

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing