During the last few years, observations have yielded an abundant population of short-period planets under 15 Earth masses. Among those, hot terrestrial exoplanets represent a key population to study the survival of dense atmospheres close to their parent star. Thermal emission from exoplanets orbiting low-mass stars will be observable with the next generation of infrared telescopes, in particular the JWST. In order to constrain planetary and atmospheric properties, we have developed models to simulate the variation of the infrared emission along the path of the orbit (IR phase curve) for both airless planets and planets with dense atmospheres. Here, we focus on airless planets and present preliminary results on the influence of orbital elements, planet rotation, surface properties and observation geometry. Then, using simulated noisy phase curves, we test the retrieval of planets' properties and identify the degeneracies.