References in classic literature ?
As these catastrophes occur, the sun will blaze with renewed energy; and it may be that some inner planet had suffered this fate.
A careful analysis of the dynamical interaction between planets, previously performed by a team led by David Nesvorny (Southwest Research Institute), predicted that this system had two planets near a two-to-one resonance (the orbital period of the unseen outer planet is exactly two times longer than the transiting inner planet).
A comparison of the two objects showed that the inner planet cannot contain more water or gas than the outer one.
The apparent diameter of an inner planet changes appreciably with its position in its orbit; it is largest at inferior conjunction, but since it is then between the Sun and the Earth it cannot be seen.
The inner planet, Kepler-47b, orbits the pair of stars in less than 50 days.
INNER PLANET Mercury is not as uninteresting as we first thought
The inner planet, Kepler-47b, is three times wider than Earth and whips around the stars every 49 days.
The larger outer planet falls just outside the outer boundary of the habitable zone and is also likely to be rocky, while the smaller inner planet is too close to the star to be habitable.
The inner planet is estimated to have be either slightly less massive than Jupiter, while the outer one may be up to 10 times as massive as the gas giant - an estimate that is in line with other optical and infrared studies of the star system.
An inner planet, PH3b, may have a rocky composition, like Earth.
The smaller inner planet, Kepler-36b, is rocky and subject to quakes and volcanic eruptions caused by the interplay of the planets' gravitational forces on each other.
What's more, the two planets have migrated into orbits that have a special gravitational synchrony--every time the outer planet makes one lap around Kepler-9, the inner planet makes two, Holman and his collaborators report online August 26 in Science.