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Exoplanets Mass Distribution

Histogram of the exoplanets mass distribution

A histogram showing the distribution of the mass lower limits of the confirmed exoplanets in a subset of the sample that have measured mass lower limits (sample snapshot for 5 August, 2012). Plotted is the percentage of the subsample of exoplanets in each mass interval. Masses are shown as ratios of the exoplanet masses to the mass of the Earth (i.e., masses are shown in units of the mass of the Earth). Data are from the Extrasolar Planets Encyclopedia. For comparison, the masses of the planets in our solar system are marked as Me, V, E, Ma, J, S, U, N, corresponding to Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune, respectively (numerical values are from

The mass distribution has a large, broad peak centered in the region of 200 to 1000 Earth masses, and a smaller peak in the region of 10 or so Earth masses. Recall that Jupiter is 317.828 times the mass of the Earth so the large peak in the mass distribution embodies the plentitude of giant planets that have been found, most notably the hot jupiters that have been found.

It is important to consider the possible selection effects when interpreting the exoplanets mass distribution. Read more about exoplanets, and the mass distribution with Exoplanets and Alien Solar Systems, which includes comprehensive references to the scientific literature, and discussion of selection effects.

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Note: The data in the histogram were derived from the sample of confirmed exoplanets at the time that the total number of confirmed exoplanets was 777 (residing in 623 alien solar systems, 105 of which harbored more than one exoplanet). Over 98.5% of the exoplanets in this sample contribute to the histogram (the remainder don't have a mass lower or upper limit estimate).
File under: What is the mass distribution of exoplanets? What is the mass distribution of extrasolar planets? What are the masses of exoplanets? How massive are exoplanets?

© Tahir Yaqoob 2011-2012.