September 15, 2011

Tatooine. Pwn'd.

Today, the discovery of the first transiting circumbinary planet orbiting two stars have just been announced. Kepler-16 (AB) b or simply Kepler-16 b has been revealed.

Kepler-16 b is 216 light years away, and it orbits around two stars that are orange and red in color, both are smaller and "cooler" than our own sun. Kepler-16b orbits them far enough such that the two stars are being felt as one source of gravity. The planet is on a stable orbit, but the movement of the two stars orbiting each other makes the Habitable Zone dynamic and could vary the temperature of that zone by at least 30 degrees. This tells us to to look at the Habitable Zone not as a fixed "place" but as something dynamic. "The notion of habitable zones in a planetary system has got to change. It's a dynamic thing," says one of the scientists.

All this makes the Kepler-16 star system a wonderful laboratory that will definitely teach us more about Habitability in the future. And it will tells us the possibility of planets around other binary Star Systems like Alpha Centauri which is just 4.2 light years away.

So what is it like on that planet? Although some describe it as "Tatooine-like", Kepler-16b is actually a cold and frigid place. It's surface may actually be different than the depicted planet in Star Wars. It's a mix of gas and rock and the temperature on its surface is described as "kind of like a nippy day on Antartica" or "like a nippy day on Mars". It's just outside the Habitable Zone (but the Kepler team is looking for an exomoon around it which may turn out to be habitable). The dramatic thing is that no two sunsets on that planet are alike. Its two suns will cast shadows with hues of orange and red. Very dramatic, indeed. I think that's what makes it "Tatooine-like".

Truly, the discovery of Kepler-16b is a landmark not only in Exoplanet Science, but also in terms of Humanity's mode of imaginative thinking because it pushes the boundaries of what we once thought were not possible. It tells us to dream bigger possibilities!

Update: There have been other planets found in binary systems in the past, but Kepler-16b has been the clearest detection yet of a transiting planet orbiting a Circumbinary System. It's the first of a new class of planets (Circumbinary Planets) that will be revealed by Kepler in the coming weeks or months. [ Hint: 150 candidate circumbinary planet candidates in 750 Kepler eclipsing binaries! in the pipeline ]

Kepler-16 (Ab)
Additions to Exoplanets in Binary Star Systems

Image: NASA/JPL-Caltech

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