Kepler Mission Options

[Hungry4info]

MahFL, the reference about Kepler is at like the last paragraph. Just search (Ctrl + F) "Kepler" and it takes you right to it ^.^

[Syrinx]

You're correct, it's not. But it does have this:

Separately, NASA's Kepler Mission will present the first results of its planet search at the American Astronomical Society meeting in Washington in January. "[The Kepler team] has already submitted 28 scientific papers based on 43 days of data or less," says MIT planet theorist Sara Seager. "It's going to be a big year for planets."

[MahFL]

Ah in my unfamiliarity with that website I did not notice the + sign.

[scalbers]

That link does not seem to be about Kepler and 28 papers......

Interesting though about the red dwarf watery planet. Will Kepler also be looking for some of these?

[Ron Hobbs]

The real planetary scientists here may have something to say about this, but I would bet that Thalassan type planets [named for the fictional waterworld of Clarke's "Songs of Distant Earth] will be quite prevalent. Kepler may well find many of them in a habitable zone.

[scalbers]

Yes, and since they would have shorter orbital periods they could dominate the initial findings.

[scalbers]

Second, I've defined five criteria:

A) Mass
Radius
C) Mean surface temperature
D) Breathable atmosphere
E) Liquid water

I wonder if Kepler or other observations would be able to address criterion C if it found a Venus like planet.

Another criterion could be density (more closely constraining mass and radius) to look for rocky planets.

[Ron Hobbs]

Kepler will be able to tell us how far away the planet is from its star and we will have very good measures of its energy output. It will be easy to figure out how much energy is delivered to the planet and how that energy is distributed. Spectral evidence of the presence of an atmosphere will probably have to come from the larger scopes.

Density is calculated from mass and radius. Mass is determined by the orbit. The reason they are suggest that this new planet is a water world is from the calculations of its density, showing that it was made up of a lot of water. I am pretty sure that Kepler will constrain the radius of exoplanets more precisely than any Earth based telescope.

Any planet with a lot of water that is within its star's habitable zone, or closer, will have a surface that is liquid water. (I can imagine an "ice cap" forming on the anti-stellar side of a tidally locked world, but that will depend on how well the atmosphere distributes the heat.) I'd be really surprised if these kind of worlds were not very common among the Earth-sized planets that Kepler finds.

[scalbers]

The tricky part of the Venus scenario is that there are two factors that add on to a first-order temperature calculation. First its high albedo should make it cooler than "expected" though placing it within habitable surface conditions. Second and more importantly its greenhouse effect makes it very much hotter as a net result. This type of thing might be more difficult to infer.

[Ron Hobbs]

Modeling the atmospheres and the effects of them on these "hot" planets is and will be tricky. Well beyond my abilities. I think that why we will need to get spectra of the worlds that Kepler discovers with larger scopes. Ultimately, this will be an important job for the JWST.

[Syrinx]

The reason they are suggest that this new planet is a water world is from the calculations of its density, showing that it was made up of a lot of water.

Rubbing alcohol has a density 90% that of H2O. How can we be so sure GJ 1214b isn't a "rubbing alcohol world"? Honest question; I don't know the answer.

[nprev]

Probability, I'd say. H2O is a far more cosmically abundant compound than any alcohol...Occam's Razor.

[scalbers]

There's a short article in the January 2010 Scientific American (p. 26) where they discuss the possibility of carbon planets. They could be made of carbon or related compounds instead of oxygen rich compounds. Maybe Kepler will find some of these?

[Jason W Barnes]

There's a short article in the January 2010 Scientific American (p. 26) where they discuss the possibility of carbon planets. They could be made of carbon or related compounds instead of oxygen rich compounds. Maybe Kepler will find some of these?

Sure it might -- but without spectroscopy it will be hard to tell which ones are Carbon-worlds and which are Oxygen worlds! The densities aren't distinct enough to allow Kepler to differentiate.

- Jason

[Greg Hullender]

. . . I would bet that Thalassan type planets [named for the fictional waterworld of Clarke's "Songs of Distant Earth] will be quite prevalent.

Thalassa was an ancient greek water goddess, and her name gets used a lot for things of this sort. For example, the ancient supercontinent, Pangaea, was surrounded by a world ocean, Panthalassa. I suspect that's where Clarke got his title. I don't think it works the other way around! ;-)

But I definitely agree that I don't know of any mechanism to soak up excess water from such a world. There may be a very narrow margin between a world with too little water and one with oceans a hundred miles deep, and the odds on getting a world that's "just right" may be fairly low. I don't know of anything planned that could answer this, though.

--Greg