Tuesday, November 06, 2007

New Exoplanet: Coyote?

Back in February I wrote about a fairly decent SF novel I was reading, Coyote by Allen Steele (it had some problems, but I liked it well enough to read the sequel, Coyote Rising). Coyote is a "novel of interstellar exploration" that starts in 2070 and involves hundreds of colonists traveling for 230 years (in "biostasis") at 20% the speed of light to reach a star system 46 light years from Earth. There they wake up and land on the fourth moon of a Saturn-like gas giant planet orbiting in the habitable zone of its star. This Earth-like moon was named "Coyote."

Today NASA announced the discovery of a fifth planet orbiting the star 55 Cancri, 41 light years from here in the constellation Cancer (more info including a cool video here). It is a remarkable achievement of observation, data collection, Doppler-shift measurement, and data reduction to tease out the properties of the star's five individual planets from 18 years of observational data from California's Lick Observatory.

What's even cooler is that while the fifth planet (which is actually the fourth in distance from its star) is also a gas giant (45 times the mass of Earth), its orbital distance (116.7 million kilometers, orbital period 260 days) puts it within the habitable zone of its star (closer to the star than we are to the sun, but the star is fainter than the sun). That means that if it has any rocky moons orbiting it, they could have liquid water on their surfaces, and where there's liquid water, there could be... you get the idea.

Of course no moons have been detected yet, but all the gas giants of our solar system have them, and it's reasonable to assume that extra solar gas giants would as well. So "Coyote" could be there, and it's 5 light years closer than in Steele's novel! Now we need to get to work on giant space-based optics so we can image those exoplanetary moons, not to mention the star ship and propulsion systems that will give us 0.2c, and the robotics and biostatasis system that will let our intrepid colonists sleep for 200 or so years on the way to their new home. This is left as an exercise for the reader.

Update: For anyone interested in more details and serious discussion, this post in Centauri Dreams is a good place to start. The comments have additional details including a link to a PDF preprint of the five-planet paper by the scientific team. As Paul notes, we are indeed entering what seems to be a golden age of exoplanet research.

1 comment:

Christopher Waldrop said...

This is absolutely fascinating. I know there's quite a bit of discussion of ways to determine whether various exoplanets could hold life (the December issue of Discover Magazine has an interview with scientist David Charbonneau who's using spectral analysis to determine the chemical composition of exoplanets). The idea of moons being potential sites for life just widens the scope.