91 Aquarii b
Encyclopedia
91 Aquarii b, also known as HD 219449 b, is an extrasolar planet
orbiting in the 91 Aquarii system approximately 148 light-years away in the constellation
of Aquarius
. It orbits at the average distance of 48.5 Gm from its star, which is closer than Mercury
is to the Sun
(57.9 Gm). The planet takes half a year to revolve around the star in a very circular orbit (e=0.003).
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
orbiting in the 91 Aquarii system approximately 148 light-years away in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
of Aquarius
Aquarius (constellation)
Aquarius is a constellation of the zodiac, situated between Capricornus and Pisces. Its name is Latin for "water-bearer" or "cup-bearer", and its symbol is , a representation of water....
. It orbits at the average distance of 48.5 Gm from its star, which is closer than Mercury
Mercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...
is to the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
(57.9 Gm). The planet takes half a year to revolve around the star in a very circular orbit (e=0.003).