I'm trying to assess the tidal stresses different exoplanets experience during their orbits. The known parameters are usually mass $M$, radius $R$, eccentricity $e$, orbital period $T$, and semi-major axis $a$ (where the mass and radius of the host star are known as well). The most straightforward way I can think of is using the tidal force imposed on the surface of the planet by the star:

$$ F_{tidal}= -2G\frac{M_*M_p}{\bar{r}^3}R_p$$

Where subscripts $*$ and $p$ represent the star and planet respectively. $\bar{r}$ is the mean distance:

$$ \bar{r} = a \left( 1+ \frac{e^2}{2} \right)$$

and then dividing it by the surface area of the planet:

$$ \tau_{tidal}= \frac{F_{tidal}}{4\pi r_p^2}$$

However, I'm not sure if there is a better (and more appropriate) way to estimate the tidal stress.


1 Answer 1


A solution to this problem, along with some applications, is provided in the paper ``The Ability of Significant Tidal Stress to Initiate Plate Tectonics'' by Zanazzi & Triaud.

More applications can be found in the work by McIntyre.


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