  We report on the discovery and validation of a transiting long-period
mini-Neptune orbiting a bright (V = 9.0 mag) G dwarf (TOI 4633; R = 1.05 RSun,
M = 1.10 MSun). The planet was identified in data from the Transiting Exoplanet
Survey Satellite by citizen scientists taking part in the Planet Hunters TESS
project. Modeling of the transit events yields an orbital period of 271.9445
+/- 0.0040 days and radius of 3.2 +/- 0.20 REarth. The Earth-like orbital
period and an incident flux of 1.56 +/- 0.2 places it in the optimistic
habitable zone around the star. Doppler spectroscopy of the system allowed us
to place an upper mass limit on the transiting planet and revealed a
non-transiting planet candidate in the system with a period of 34.15 +/- 0.15
days. Furthermore, the combination of archival data dating back to 1905 with
new high angular resolution imaging revealed a stellar companion orbiting the
primary star with an orbital period of around 230 years and an eccentricity of
about 0.9. The long period of the transiting planet, combined with the high
eccentricity and close approach of the companion star makes this a valuable
system for testing the formation and stability of planets in binary systems.
