Calculating the Probability of Kepler-452b as a Rocky Planet in the Habitable Zone

Kepler-452b was announced as a super-Earth exoplanet in 2015. It became the first potentially rocky Earth-like world to be found orbiting within the habitable zone of a Sun-like star.

This project shows that it is highly probable that Kepler-452b is indeed a rocky, habitable-zone planet. I assume the small planet approximation and circular orbit. I fix some of the transit and orbital parameters, including inclination, transit duration, and orbital period, with the literature values (Jenkins et al. 2015) when modeling the data. I generate samples for planetary radius and equilibrium temperature by using a Markov Chain Monte Carlo (MCMC) algorithm and using an independent set of stellar posterior sample for stellar radius and effective temperature. For my purposes here, I consider the planet to be in the habitable zone if its equilibrium temperature is within the habitable zone temperature limits of 207.5 K and 320.4 K, and I consider the planet to be rocky if its radius is below the rocky-gas divide (1.23 earth-radii).

I run the MCMC algorithm for a million successful jumps and define the burn-point as the first log-posterior that exceeds the median of the log-posterior chain. I find that it is 97% probable that Kepler-452b is a rocky, habitable zone planet and estimate a planetary temperature and radius of approximately 272 K and 1.06 earth-radii respectively.