Two questions:
I assume a biotic planet is defined as a planet which currently contains living bacteria or something living derived from bacteria. Is this correct?
I think I've spotted an error, but wanted to check. On page 3, Rb is defined as "the rate at which stars suitable for the evolution of biotic life are formed in the Galaxy." Based on the parameters given, shouldn't this be the rate at which planets suitable for the evolution of biotic life are formed in the Galaxy?
Also, seeing stuff like this really bugs me:
top of page 2: "Recent analyses of the Kepler statistics showed that about 20% of all Sun-like stars have Earth-sized planets orbiting within the habitable zone [Petigura, Howard and Marcy 2014]."
2nd paragraph of page 3: "Analyses of the Kepler results shows that 7-15% of the Sun-like stars have an Earth-sized planet within their habitable zone [Petigura et al., 2014]"
That's a pretty glaring error to be making. This isn't a top journal, but it isn't an obscure one either. http://eigenfactor.c...
On the abundance of extraterrestrial life after the Kepler mission Amri Wandel
Some recent calculation of the Drake Equation with estimates of the likelihood and logevitiy of civilizations
Related: The Great Filter and Planets in the habitable zone, the Drake Equation, and the Great Filter