Formation and evolution of the Solar System owe its substantially lower mass simply to having formed a few million years after Jupiter, when there was less gas available to consume. T Tauri stars like the young Sun have far stronger stellar winds than more stable, older stars. Uranus and Neptune are thought to have formed after Jupiter and Saturn did, when the strong solar wind had blown away much of the disc material. As a result, those planets accumulated little hydrogen and helium—not more than each. Uranus and Neptune are sometimes referred to as failed cores. The main problem with formation theories for these planets is the
HD 170469 b HD 170469 b HD 170469 b is a gas giant exoplanet located approximately 212 light-years away in the constellation Ophiuchus, orbiting the star HD 170469. This planet was discovered in April 2007. The star is 1.1 solar mass and the planet is at least 67% the mass of Jupiter, orbiting about half the distance of Jupiter from the Sun. The mass value is only minimum since the inclination is unknown. The orbital distance is more than twice the distance from Earth to the Sun, although taking over three Earth years to orbit the star. The combined distance and period would