  A comprehensive approach is provided to the study of both S-type and P-type
habitability in stellar binary systems, which in principle can also be expanded
to systems of higher order. P-type orbits occur when the planet orbits both
binary components, whereas in case of S-type orbits the planet orbits only one
of the binary components with the second component considered a perturbator.
The selected approach encapsulates a variety of different aspects, which
include: (1) The consideration of a joint constraint including orbital
stability and a habitable environment for a putative system planet through the
stellar radiative energy fluxes ("radiative habitable zone"; RHZ) needs to be
met. (2) The treatment of conservative, general and extended zones of
habitability for the various systems as defined for the Solar System and
beyond. (3) The providing of a combined formalism for the assessment of both
S-type and P-type habitability; in particular, mathematical criteria are
presented for which kind of system S-type and P-type habitability is realized.
(4) Applications of the attained theoretical approach to standard (theoretical)
main-sequence stars. In principle, five different cases of habitability are
identified, which are: S-type and P-type habitability provided by the full
extent of the RHZs; habitability, where the RHZs are truncated by the
additional constraint of planetary orbital stability (referred to as ST and
PT-type, respectively); and cases of no habitability at all. Regarding the
treatment of planetary orbital stability, we utilize the formulae of Holman &
Wiegert (1999) [AJ 117, 621], as also used by previous studies. In this work we
focus on binary systems in circular orbits. Future applications will also
consider binary systems in elliptical orbits and provide thorough comparisons
to other methods and results given in the literature.
