High Quality Content by WIKIPEDIA articles! There are (as of February 19, 2013) 128 known multiplanetary systems (i.e. stars with at least two confirmed planets), beyond our Solar System. The star table below contains information about the coordinates, spectral and physical properties, and number of confirmed planets (as of July 7, 2011). The two most important stellar properties are mass and metallicity because it determines how these planetary systems form. The higher mass and metallicity tend to have more planets and more massive planets.