Sizzling Weather On a Dive-Bombing Planet 57
The Bad Astronomer writes "A massive planet orbiting the star HD 80606 is on a roller-coaster orbit: it dive bombs the star, in just 55 days dropping from over 120 million km to just 4 million km from the star's surface! Astronomers used the Spitzer Space Telescope to observe the heat from the planet as it gets blasted by its star, and used that data to make a beautiful computer-modeled image of what the planet must look like. Their results: an ube-rviolent storm that acts as if a bomb were exploded in the planet's atmosphere."
Re:Rotation Period (Score:4, Informative)
If this planet is in a 1/1 resonance it will have one side which never gets baked at close approach, so conditions on the surface may not be as bad as they first seem.
If the winds are strong enough in the atmosphere and the atmosphere is thick enough, it may not matter what side of the planet you're on. Just like Venus, which rotates very slowly, but is pretty much the same sizzling hellhole regardless of whether you look at the day or night side.
Don't dumb it down. (Score:5, Informative)
Dive-bombing? This isn't Pearl Harbour the movie. Try "highly elliptical" orbit, and "close approach" or "close proximity". This is /. not 5th grade.
Re:plantary Promethian punishment (Score:4, Informative)
With conditions this extreme, I wonder if there is an atmosphere. Would it not get ripped away?
Considering that the planet in question has four times the mass of Jupiter, I would assume that it has more than enough gravity to hang on to its atmosphere.
Re:Don't dumb it down. (Score:5, Informative)
Highly elliptical means that the object's Orbital Eccentricity [wikipedia.org] is high - in this case, 0.927. A circle has eccentricity 0, and the Earth has an eccentricity of about 0.0167. If you don't consider that planet's orbit to be highly elliptical, compare its 0.927 to that of Halley's Comet: 0.967.
Note that there can be eccentricities >= 1, but they're not closed orbits.
For an interesting orbit, consider the Molniya Orbit [wikipedia.org] and its kin used by satellites that need long dwell times over high latitude areas.
Re:Rotation Period (Score:3, Informative)
The orbit is very highly eccentric, which means the usual theory of tidal locking doesn't apply. The research uses a theory of spin pseudo-synchronization (Eq. 18 of this paper [arxiv.org]) to derive the planet's rotation rate in relation to its orbit. They do note there is an alternate theory of spin synchronization that, for simplicity, they didn't consider in this paper.