Habitable Planets for Man

70 Ophiuchi absolute visual magnitude altitude angular apparent visual magnitude approximately assumed astronomical units billion binary star systems breathable atmosphere capture cent centimeter component cubic parsec detected Earth masses Earth's surface ecosphere equator Eridani escape velocity estimate exist extreme forms free oxygen function Galaxy gases grams habitable planets helium human hydrogen illumination isolated star Jupiter latitude less light light-years limit luminosity main sequence main-sequence stars Mars mass range mean distance millimeters of mercury Moon Neptune nitrogen number of habitable oblateness oceans orbital eccentricity parameters parsec partial pressure planet in orbit planet orbits planetary atmosphere planetary mass planetary orbits planetary systems present primary properties radiation radius rate of rotation regions relationship relative rotation rate satellite Saturn seen solar mass solar system space spectral class stable stellar mass surface gravity Table terrestrial planets tidal braking tolerable Uranus values Venus volcanic water vapor