COROT discovers COROT-Exo-7b, with a diameter less than twice that of Earth

Wednesday, February 04, 2009

Wow, this is an exciting find. We're getting very close now.

The new find, COROT-Exo-7b, is different: its diameter is less than twice that of Earth and it orbits its star once every 20 hours.
Every 20 hours, hmm? That must mean that:
It is located very close to its parent star, and has a high temperature, between 1000 and 1500*C. Astronomers detected the new planet as it transited its parent star, dimming the light from the star as it passed in front of it.
Spaceref doesn't have all that much information about the new planet though (such as where the system is located compared to us), so let's take a look at this article as well:
European astronomers say they have found a "super-Earth" that's less than twice as wide as our planet, but up to 11 times more massive and hellishly hot.
This transit method is how researchers detected COROT-Exo-7b, circling a sunlike star about 457 light-years from Earth.
The article is also detailed enough to answer my question about whether one side of the planet could be frozen if it were tidally locked to its star:

Looking beyond the numbers, Exo-7b would be an exotic - if not exactly comfortable - place to visit. The researchers speculate that the planet might be rocky like Earth, and covered in liquid lava. Or it could be made up of water and rock in equal amounts, and possess a water-vapor atmosphere.

Wait a minute ... water? Wouldn't any water on Exo-7b boil off into space?

"It's even beyond the point of boiling: It's in the state called super-critical water, which is neither a gas nor a liquid," Rouan wrote. "However, vapor is its best approximation. Note that this possibility of having water on this planet is just a viable hypothesis, not the most probably at present. A more precise response in a few weeks or months probably."

Fridlund said the water might even exist as ice, if the conditions were just right. "If the rotation of the planet is bound (like our moon is), and it turns the same side toward its star at all times, the other hemisphere may be very cold, and water could exist as ice on the surface."

It then gets into the upcoming Kepler Mission and how the best is yet to come in terms of discovering extrasolar planets. On a political note, as I wrote in November the first of many second Earths will be discovered during the Barack Obama presidency so I that's the administration that will be making decisions about what to do afterwards. It's true that we have no way of getting to a second Earth after we've discovered one, but we still have the capability to send radio signals at the speed of light, and the issue will probably come up as to whether we should try broadcasting a signal to the new planet(s) just in case there's life there and communicating with it might be a good idea, or whether we should avoid doing that considering our lack of technological prowess at the moment and out of the so-called "abundance of caution", just in case letting the universe know that we exist might be a bad idea.

Of course, we send out radio signals all the time but I'm talking about a very directed broadcast that is intended to announce our presence to the rest of the universe.

Other decisions to make would probably involve improving our ability to observe these planets, such as reinstating the Terrestrial Planet Finder or something similar. We'll be finding Earth-sized planets in the next few years, and of course we'll still be at the "barely able to make LEO" phase so the only way we'll be able to respond to that is to increase our ability to observe them. Everything else is impossible at the moment. I suspect we'll see an increase in the budget of these planet-observing missions once we've found one or more of these planets.

Edit: has some more info on the planet in chart form.


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