Not exact matches
Instead, it would have spent a long time in a
stable orbit around a single
star before encountering the dangerous influence of Alpha Centauri A and B.
Now, Hippke and Heller show that a combination of the
stars» gravity and radiation pressure from their photons can bring the craft into a
stable orbit around one of the
stars, then
around the tantalising planet (Astrophysical Journal Letters, doi.org/bx8t).
He pointed out that there are many close -
orbiting planets
around middle - aged
stars that are in
stable orbits, but his team doesn't know how quickly this young planet is going to lose its mass and «whether it will lose too much to survive.»
In a small number of the simulations, it eventually wound up in a
stable orbit around one of the
stars.
An Earth - type planet could have liquid water in a
stable orbit centered
around 0.036 AU from
Star B — well within the orbital distance of Mercury in the Solar System.
An Earth - type planet could have liquid water in a
stable orbit centered
around 1.18 AU from
Star A — between the orbital distances of Earth and Mars in the Solar System.
Assuming that the spectroscopic companion B does not preclude a
stable inner planetary
orbit, the distance from
Star A where an Earth - type planet would be «comfortable» with liquid water is centered
around only 0.457 AU — between the orbital distances of Mercury and Venus in the Solar System.
The analyses did not resolve whether the perturbing body
orbits Sirius A or B, although dynamical simulations suggest that
stable orbits exist
around both
stars at circumstellar distances up to more than half the binary system's closest separation of 8.1 AUs (Daniel Benest, 1989).
However, if the existence of a relatively close, second companion (see
Star Bc below)
around Bab — with an orbital period of 2.2 to 2.9 years or less — is confirmed, then a planetary
orbit in
Star Ba's water zone may not be
stable over the long run.
An Earth - type planet could have liquid water in a
stable orbit centered
around 3.5 AU (within a predicted habitable zone ranging between 2.3 and 4.8 AUs) from
Star A — between the orbital distances of the Main Asteroid Belt and Jupiter in the Solar System (NASA
Stars and Exoplanet Database).
Indeed,
stable orbits may extend as far as one third of the closest separation between any two
stars in a binary system, but according to NASA's Kepler Mission team, numerical integration models have shown that there is a range of orbital radii between about 1/3 and 3.5 times the stellar separation for which
stable orbits around two
stars are not possible (Holman and Wiegert, 1999; Wiegert and Holman, 1997; and Donnison and Mikulskis, 1992).