MASS–RADIUS RELATION FOR ROCKY PLANETS BASED ON PREM

By L. Zeng, D. Sasselov, S. Jacobsen. 2015

211 citations recorded by the source corpus.

Several small dense exoplanets are now known, inviting comparisons to Earth and Venus. Such comparisons require translating their masses and sizes to composition models of evolved multi-layer interior planets. Such theoretical models rely on our understanding of the Earth’s interior, as well as independently derived equations of state, but so far have not involved direct extrapolations from Earth’s seismic model: the Preliminary Reference Earth Model (PREM). To facilitate more detailed compositional comparisons between small exoplanets and the Earth, we derive here a semi-empirical mass–radius relation for two-layer rocky planets based on PREM, R R ⊕ = ( 1.07 − 0.21 · CMF ) · M M ⊕ 1 / 3.7 ?> , where CMF stands for core mass fraction. It is applicable to 1 ∼ 8 M⊕ and a CMF of 0.0 ∼ 0.4. Applying this formula to Earth and Venus and several known small exoplanets with radii and masses measured to better than ∼30% precision gives a CMF fit of 0.26 ± 0.07.

Subfields: Astronomy and Astrophysics, Geophysics

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Geophysics

Citations in the corpus

How to Characterize Habitable Worlds and Signs of Life (2017, methodology): “Data are from http://www. exoplanet.eu (accessed February 2017) and models following Zeng et al. (2016).”
The Cosmic Shoreline: The Evidence that Escape Determines which Planets Have Atmospheres, and what this May Mean for Proxima Centauri B (2017, methodology): “7 (Zeng et al. 2016), we estimate vesc = 12.7 km s−1.”
PROBABILISTIC FORECASTING OF THE MASSES AND RADII OF OTHER WORLDS (2016, methodology): “Parametric models, in particular power laws, have long been popular for modeling the MR relation with many examples even in the recent literature (e.g., Valencia et al. 2006; Weiss et al. 2013; Hatzes & Rauer 2015; Wolfgang et al. 2015; Zeng et al. 2016).”
The Transit Light Source Effect: False Spectral Features and Incorrect Densities for M-dwarf Transiting Planets (2017, background): “To place the systematic radius errors in context, the difference in radius between an entirely rocky composition and a planet with 25% H2O by mass for planets with masses between 0.125 and 32 Earth masses is 10-12% (Zeng et al. 2016, Table 2), illustrated by the shaded regions in Figure 9.”
Observing the Atmospheres of Known Temperate Earth-sized Planets with JWST (2017, methodology): “We use an empirical mass–radius relationship from Weiss & Marcy (2014), which is consistent with a rocky terrestrial composition (Zeng et al. 2016).”
The CARMENES Search for Exoplanets around M Dwarfs: A Low-mass Planet in the Temperate Zone of the Nearby K2-18 (2018, background): “Theoretical two-layer models obtained from Zeng et al. (2016) are overplotted.”