Blog #19, Astrobite sumamry, Earth 2.0

In July, Nasa's Kepler Mission discovered the first exoplanet to exhibit a similar orbit to Earth, rotating its star in a roughly annual pattern. The planet, known as Kepler 452b is considered a small planet, meaning it is less than twice the size of the Earth. The year long orbit pattern led researchers to explore more about Kepler 452b, one of 5000 exoplanets discovered over the past 4 years by the Kepler program. The Nasa crew described Kepler 452b as an "older, bigger cousin to Earth."

The Kepler program images a particular area of the night sky and tracks the flickering of the light from the stars to track the planets orbiting the respective stars. Kepler 452b's star is roughly 1400 lightyears away from Earth making tracking the exact orbit a very difficult challenge. Although the light curves are very accurate, there are many other objects that can cause the same .02% drop in light from the star that the exoplanet would. To try and confirm the existence of a planet, researchers compared typical light curves of other potential objects such as larger planets or background stars, to the expected light curve of the exoplanet's passing. They placed 424:1 odds, pretty good for astronomical events.

After further experimentation and data analysis, researchers tried to narrow down similarities between Kepler 452b and Earth. They found the Keplerian planet to have a radius 1.6 the size of Earth's. More excitingly, they claimed that there was a 96% chance that the planet was in the habitable zone of its solar system, meaning it sits at a distance from its star similar to the distance that Earth sits at in our solar system. Researchers also believe that the surface of the planet could be rocky, similar to Earth's.

While we should by no means pack our suitcases and get ready to travel the 1400 lightyears to Kepler 452b, the article does provide a very optimistic and interesting opportunity to look at habitable exoplanets.

Work used:
http://astrobites.org/2015/08/03/have-we-really-found-earth-2-0/
http://i.space.com/images/i/000/049/219/i02/452b_ArtistConcept.jpg?1438295759