Characteristics
Given the planet's high mass, it is likely that it is a gas giant with no solid surface and surface gravity of over 25 times that of Earth. Since the planet has only been detected indirectly through observations of its star, properties such as its radius, composition, and temperature are unknown.
Upsilon Andromedae d lies in the habitable zone of Upsilon Andromedae A as defined both by the ability for an Earthlike world to retain liquid water at its surface and based on the amount of ultraviolet radiation received from the star. Simulations suggest that even on eccentric orbits, terrestrial planets may be able to support liquid water throughout the year. Such an Earthlike moon would have summer and winter corresponding to periastron and apastron respectively, worldwide at the same time, rather than alternating between northern and southern hemispheres as on Earth due to an axial tilt. This suggests that if sufficiently large moons of Upsilon Andromedae d exist, they may be able to support extraterrestrial life.
Read more about this topic: Upsilon Andromedae D