Eta2 Hydri b
Encyclopedia
Eta2 Hydri b commonly known as HD 11977 b, is an extrasolar planet
that is approximately 217 light-year
s away in the constellation
of Hydrus
. The presence of the planet around an intermediately massive giant star
provides indirect evidence for the existence of planetary system
s around A-type stars.
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...
that is approximately 217 light-year
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...
s 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 Hydrus
Hydrus
Hydrus is a small constellation in the southern sky, created in the sixteenth century. Its name means "male water snake", and it should not be confused with Hydra, a much larger constellation which represents a female water snake.-History:...
. The presence of the planet around an intermediately massive giant star
Giant star
A giant star is a star with substantially larger radius and luminosity than a main sequence star of the same surface temperature. Typically, giant stars have radii between 10 and 100 solar radii and luminosities between 10 and 1,000 times that of the Sun. Stars still more luminous than giants are...
provides indirect evidence for the existence of planetary system
Planetary system
A planetary system consists of the various non-stellar objects orbiting a star such as planets, dwarf planets , asteroids, meteoroids, comets, and cosmic dust...
s around A-type stars.