Sizzling Weather On a Dive-Bombing Planet

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."

Comments

Rotation Period

[MichaelSmith]

A planet which gets really close to its primary is more likely to be tide locked because of the energy lost when the tidal bulge moves around. Mercury is in a 2/3 resonance for this reason.

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.

Re:Rotation Period

[Ihlosi]

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.

Re:Rotation Period

[Ambitwistor]

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) 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.

Whoa!

[dov_0]

That's the biggest BBQ I've ever heard of!

Maybe the planet is just

[antifoidulus]

really really drunk.

Don't dumb it down.

[syousef]

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:Don't dumb it down.

[Muad'Dave]

Highly elliptical means that the object's Orbital Eccentricity 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 and its kin used by satellites that need long dwell times over high latitude areas.

Re:Don't dumb it down.

[Nimey]

5km/sec? I don't understand that. What is that in libraries of congress?

mod parent up

[MichaelSmith]

...though "Flamebait" seems strangely appropriate for this topic.

plantary Promethian punishment

[Bearhouse]

With conditions this extreme, I wonder if there is an atmosphere. Would it not get ripped away?
The article talks about supersonic winds - but how do we know?

Perhaps the atmosphere regenerates as the planet moves away from the star, only to be ripped away again in some kind of Promethian nightmare

Re:plantary Promethian punishment

[Ihlosi]

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:plantary Promethian punishment

[Anonymous Coward]

Within the article, you'll find that this is a gas giant. It's so large that its own gravitational effect causes its sun to swell on approach.

With 5km/s winds?

[Moraelin]

First of all, we're talking a planet considerably heavier than Jupiter, so presumably a gas giant. Or anyway it will have quite the pressure.

Second they said it produced explosive winds, up to 5 km/s. (Or "fucking unbelievably fast" in imperial units;) Because the air heats from 500 degrees to 1200 degrees on the hot side within hours, and expands, rushing towards the colder side.

That's over 5 times the muzzle velocity of an M16, BTW.

So, yeah, the conditions on the surface might not be as bad as they seem... as long as you don't mind winds strong enough to blast you to bits, not to mention that they're 1200 degrees hot ;)

Band structure

[InfiniteLoopCounter]

Since fusion is not happening on the planet and it is a large gas planet, with a regular orbit one might expect a band structure of the atmosphere. As it is four times the mass of Jupiter (and thus likely larger), one might also expect that the storms are more intense, numerous, long-lived, and larger than on Jupiter occurring within the bands.

My question to someone more knowledgeable is whether or not such a planet, as described in the article, could sustain some sort of atmospheric band structure on one side of the planet? And, if so, could it maintain such a structure when close to its star? Given best circumstances of course, such as the geometry of the aforementioned prolate spheroid.

Re:Band structure

[Urkki]

As it is four times the mass of Jupiter (and thus likely larger),

Actually, Jupiter is about as big as they get, diameter-wise, all the way to brown dwarf stars. As mass increases, they only get denser, not bigger. Just consider Jupiter and Saturnus, their size is pretty close, though Jupiter has more than three times the mass

Reminds me of Nightfall

[PetoskeyGuy]

Civilization periodically destroyed every period due to the unique orbit of the planet.