  Aims: In this study we assess the habitability of HD85512b, a 3.6M_Earth
planet orbiting a K5V star. The radial velocity data and orbital parameters for
HD 85512 b have just been published, based on data from the dedicated
HARPS-upgrade GTO program. Methods: This paper outlines a simple approach to
evaluate habitability of rocky planets from radial velocity (RV) searches by
using atmospheric models of rocky planets with H2O/CO2/N2 atmospheres, like
Earth. We focus our analysis on HD 85512 b. To first order the limits of the
Habitable Zone depend on the effective stellar flux distribution in wavelength
and time, the planet's Bond albedo, and greenhouse gas effects in this
approach. We also discuss the dependence of habitability on the measurement
accuracies. Results: We provide a simple set of parameters which can be used
for evaluating current and future planet candidates from RV searches for their
potential habitability. We find that HD 85512 b could be potentially habitable
if the planet exhibits more than 50% cloud coverage. HD 85512 b is, with Gl 581
d, the best candidate for exploring habitability to date, a planet on the edge
of habitability.
