This site will close on April 30th, 2020.

Our database knows that
4141 exoplanets
are orbiting 3078 stars.

Its most recent synchronization with Exoplanets Archive
was produced on March 19, 2020.

Earth Similarity Index is known for 37% of exoplanets.
Habitable zone limits are known for 90% of host stars.


Measured and Calculated Values

The Exoplanets Archive, our source of data, provides mostly measured values for various parameters of exoplanets and their stars. Some of the figures valuable for the diagrams on our site are calculated from the measured data, using the methods detailed below.

st_lum column value (stellar luminosity in solar units), present in the original data, is available in the Archive only for a small fraction of entries (about 15% in May, 2016) and it is expressed in log(solar) units, which sometimes may not be very convenient for our usage.

We used the stellar luminosity formula from the Planetary Habitability Laboratory page in order to re-calculate the stellar luminosity values for our database. It increased the percentage of available data up to 88% for this parameter.

Insolation Flux

pl_insol column value (insolation flux) is derived from stellar luminosity and distance from host star values. In the Archive, this value is available for only about 1.5% of registered planets, which is very few, taking into account that it is critical for ESI calculation.

The formula cited on page 8 of this Philip Kaaret's presentation helped us to calculate the insolation flux for 44% of registered exoplanets.

Habitable Zone

The limits of stars' habitable zones are not included into the data available from the Archive. The implementation of their calculation is explained on a dedicated page.

Earth Similarity Index

The Earth Similarity Index is not present in the data from the Archive, so we implemented it as function of a planet's stellar flux and radius, according to the formula available from the Planetary Habitability Laboratory page.