i}}\,} 對於太陽系外的恆星系統和行星系而言,軌道傾角0°或180°代表面對觀測者的軌道;而傾角90°的軌道則代表側面對著觀測者的軌道。 Kuchner, Marc J. A Minimum-Mass Extrasolar Nebula. The American Astronomical Society
Marocco, Federico; Cayago, Alfred J.; Smart, R. L.; Eisenhardt, Peter R.; Kuchner, Marc J. The Field Substellar Mass Function Based on the Full-sky 20 pc Census