Statistical tools

Exploring the properties of the thousands of exoplanets in the database requires statistical tools. The portal offers three tools on this page :

  • HISTOGRAM represents the number/proportion of exoplanets as a function of the values ​​of the chosen parameter.
    Histogram of planet masses (in Jupiter mass). The axes are in linear scale
  • SCATTER represents exoplanets by points whose coordinates are two parameters of your choice. The colors represent the exoplanet detection modes.
    Diagram of the orbital periods ? of the planets (in days) as a function of their masses (in Jupiter mass). The color corresponds to the method of discovery of the exoplanet. The axes are in logarithmic scale.
  • POLAR represents exoplanets by points arranged radially according to their distance from the Sun.

On the diagram and histogram tool, you can choose the parameters and options for the figure (parameter value range, switching to log, adding error bars, saving the figure, the ability to configure the sizes and colors of the plot points, and choosing a cumulative histogram).
Above the figure, you can choose confirmed exoplanets (preferred), candidates, and planets with undetermined status (retracted). You can also choose planets based along to their discovery method.

On the polar view, the color of the points is associated with a parameter of your choice, including the irradiation received by the planet compared to the irradiation received by the Earth.

Observational Bias :

The histogram shows that there are more small planets than large ones (by mass range). Since small planets are harder to detect, there are actually more small planets than massive planets.

In the diagram, we see few exoplanets on the left side of the figure, i.e., low-mass exoplanets. This is because the instruments are not sensitive enough to detect small exoplanets. This is an observational bias. All detection methods have observational biases.

Understanding these biases is extremely important to access the properties of exoplanet populations.

The diagram also shows the complementarity of detection methods, which are sensitive to different exoplanets.