### HEC: Exoplanets Calculator

Here is an online calculator for some important quantities related to exoplanets and planetary habitability
. They are conveniently adapted to use Sun and Earth units in most cases. Equations are shown with any constants in metrics units.

We are still working with the construction of the calculators page.

## Stellar Properties

Stellar Luminosity

Stellar luminosity in solar units given the star radius (R) in solar units and temperature (T) in kelvins.
$\large&space;\frac{L_{\star}}{L_{\odot&space;}}=\left&space;(&space;\frac{R_{\star}}{R_{\odot&space;}}&space;\right&space;)^{2}&space;\left&space;(&space;\frac{T_{\star}}{T_{\odot&space;}}&space;\right&space;)^{4}&space;\;&space;\;&space;\;&space;\left.\begin{array}{ll}&space;R_{\odot&space;}&space;=&space;6.955\times&space;10^8&space;\;\textup{m}\\&space;T_{\odot&space;}&space;=&space;5780&space;\;\textup{K}\\&space;L_{\odot&space;}&space;=&space;3.846\times&space;10^{26}&space;\;\textup{W}&space;\end{array}\right.$

## Planetary Properties

### Planet Equilibrium Temperature

The equilibrium temperature of a planetary body is generally lower than its actual surface temperature, which depends on any atmospheric greenhouse effect. For example, a planet with a similar greenhouse of Earth would have a surface temperature 33 K over its equilibrium temperature. This calculation assumes an emissivity of 1.0 and that the planet is efficiently distributing heat around its surface (i.e. planet is not tidally locked).

### Earth Similarity Index (ESI)

Coming soon!

Please report any questions, problems, or suggestions to abel.mendez@upr.edu