Beta Hydri (β Hyi, β Hydri) is a star in the constellation Hydrus. (Note that Hydrus is not the same as Hydra.)
It is about 24.4 light years away from Earth. It is larger and slightly more massive than the Sun.
At around 150 BC, this star was two degrees away from the southern celestial pole. It is currently the nearest relatively bright star to the southern pole.
In 2002 Endl et al. inferred the possible presence of an unseen companion orbiting Beta Hydri as hinted by radial velocity linear trend with a periodicity exceeding 20 years. A substellar object with minimum mass of 4 Jupiter masses and orbital separation of roughly 8 AUs could explain the observed trend. If confirmed, it would be a true Jupiter-analogue, though 4 times more massive. So far no planetary/substellar object has been certainly detected.
Quite often used in Space Opera:
- Frontier?: Elite II? and Frontier: First Encounters?, computer games. Beta Hydri is controlled by the Federation. It has two Earth-like planets (one of which is a terraformed world) and several billion people in residence. It is close to Imperial space and is thus a popular port to find the riskier Federal missions that involve incursions into the Empire. In First Encounters, Beta Hydri is involved in two hand-coded missions that occur early in the game.
- Uller Uprising, novel by H. Beam Piper? (Twayne, 1952). Uller?, a colonized planet with silicon-based life forms, is in the Beta Hydri system.
- "Silvereyes" is a human colony world orbiting Beta Hydri in The Color of Sunfire by Larry Niven. This is a short story set in his Known Space series.
- In C.J. Cherryh's Alliance Union universe it is the location of planet Istra.