70 Virginis b is an extrasolar planet approximately 60 light-years away in the constellation of Virgo. Announced in 1996 by Geoffrey Marcy and R. Paul Butler, 70 Virginis was one of the first stars confirmed to have planets orbiting it. When first announced, 70 Virginis b was considered to be within its star's habitable zone, but it was later confirmed that the planet has an eccentric orbit, closer to its parent.
The exoplanet 70 Virginis b (min mass ~7.5 MJ) as rendered by Celestia
Radial velocity changes over time of 70 Virginis caused by the orbit of 70 Virginis b.
In astronomy and astrobiology, the habitable zone (HZ), or more precisely the circumstellar habitable zone (CHZ), is the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressure. The bounds of the HZ are based on Earth's position in the Solar System and the amount of radiant energy it receives from the Sun. Due to the importance of liquid water to Earth's biosphere, the nature of the HZ and the objects within it may be instrumental in determining the scope and distribution of planets capable of supporting Earth-like extraterrestrial life and intelligence.
A diagram depicting the habitable zone boundaries around stars, and how the boundaries are affected by star type. This plot includes Solar System planets (Venus, Earth, and Mars) as well as especially significant exoplanets such as TRAPPIST-1d, Kepler-186f, and our nearest neighbor Proxima Centauri b.
Natural shielding against space weather, such as the magnetosphere depicted in this artistic rendition, may be required for planets to sustain surface water for prolonged periods.
Earth's hydrosphere. Water covers 71% of Earth's surface, with the global ocean accounting for 97.3% of the water distribution on Earth.
Artist's concept of a planet on an eccentric orbit that passes through the HZ for only part of its orbit
