Moderate Mammal wrote:
snip
http://tinyurl.com/4d4hy
http://space.com/scienceastronomy/03...et_direct.html
snip
Actually, I meant that the orbit seemed too close for comfort meaning
the planet wasn't swallowed because of the Star's gravitational pull.
The article doesn't say much about the relative sizes of the planet
and the star, so you can't really tell how close they are. At any
rate (addressing your comment to Colin) planetary orbits don't need
to be "sustained"; they're generally stable over billions of years.
As long as a planet's not so close to the star that it boils away or
that it experiences significant drag from the star's atmosphere or
corona, there's no kinematic lower limit for the size of its orbit.
The smaller the orbit, the faster the planet travels, matching the
inward gravitational pull with forward (i.e. outward) momentum.
--
Odysseus