Monday, June 20, 2016

Kepler-452b is a Potentially Earth-Like Planet

Kepler-452b is a transiting, potentially rocky planet in the habitable zone of its host star. Its discovery was announced by Jenkins et al. (2015) after a search through four years of data collected by NASA's Kepler space telescope which hunts for planets by looking for small dips in a star's brightness when a planet happens to pass in front of it. Kepler-452b is estimated to have ~1.63 times the radius of Earth and it orbits its Sun-like host star every 384.8 days. The transit of Kepler-452b in front of its host star has a transit depth of roughly 200 ppm (parts per million) and a transit duration of roughly 10.6 hours.

Kepler-452b orbits its host star within the habitable zone and at its distance from its host star, it receives only 10 percent more flux than Earth gets from the Sun. Kepler-452b has always been in the habitable zone of its host star and it is expected to remain there for another ~3 billion years. The equilibrium temperature on Kepler-452b is estimated to be ~265 K. For comparison, the equilibrium temperature of Earth is 255 K.

Interior models suggest that the likelihood of Kepler-452b being a rocky planet is somewhere between 49 to 62 percent. The host star of Kepler-452b has ~1.11 times the radius and ~1.037 times the mass of the Sun, and its estimated effective temperature is 5757 ± 85 K. Furthermore, the host star of Kepler-452b is estimated to be 6 ± 2 billion years old. Because Kepler-452b is expected to have a relatively low-mass and its host star is relatively faint, measuring the mass of Kepler-452b through radial velocity observations will be unlikely in the near future.

Jenkins et al. (2015), "Discovery and Validation of Kepler-452b: A 1.6-Re Super Earth Exoplanet in the Habitable Zone of a G2 Star", arXiv:1507.06723 [astro-ph.EP]