Iota Horologii b
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| Extrasolar planet | List of extrasolar planets | |
|---|---|---|
 (Artist's impression) |
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| Parent star | ||
| Star | Iota Horologii | |
| Constellation | Horologium | |
| Right ascension | (α) | 02h 42m 31.65s |
| Declination | (δ) | 02° 42′ 31.65″ |
| Distance | 50.6 ly (16.8 pc) | |
| Spectral type | G0Vp | |
| Orbital elements | ||
| Semimajor axis | (a) | 0.91 AU |
| Eccentricity | (e) | 0.22±0.06 |
| Orbital period | (P) | 311.3±1.3 d |
| Angular distance | (θ) | 58.71 mas |
| Longitude of periastron |
(ω) | 78.9±13.1° |
| Time of periastron | (T0) | 2,451,308.8±10.4 JD |
| Semi-amplitude | (K) | 57.1±5.2 m/s |
| Physical characteristics | ||
| Mass | (m) | >2.24±0.13 MJ |
| Discovery information | ||
| Discovery date | July 29, 1998 | |
| Discoverer(s) | Kürster et al. | |
| Detection method | Doppler Spectroscopy | |
| Discovery status | Published | |
| Other designations | ||
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HR 810 b
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Iota Horologii b, also known as HR 810 b, is an extrasolar planet orbiting the solar twin star Iota Horologii approximately 50 light-years away in the constellation Horologium. Iota Horologii b has a minimum mass 1.94 times that of Jupiter, however preliminary astrometric measurements suggest that the object may be around 24 Jupiter masses and would therefore be a brown dwarf. Iota Horologii b was the first extrasolar planet discovered to be orbiting in the habitable zone of its parent star and is a prototype planet of gas giants that has an insolation similar to Venus.
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[edit] Characteristics
Iota Horologii b was the first planet to be found orbiting within its parent star's habitable zone. But having an eccentric and closer orbit than the Earth, Iota Horologii b is though to have an insolation similar to Venus. This makes Iota Horologii b a prototypical planet commonly quoted as a Sulfurous Cloud Giants (or sulfur giant). Because of this, Iota Horologii b might be yellowish-green in color, with an atmosphere of hydrogen, helium, water and sulfuric acid.
Though no natural satellites were discovered around any extrasolar planet, the possibility of a moon around Iota Horologii b seems likely. The maximum stable prograde (or stability of a moon) around Iota Horologii b is calculated at be at approximately 4,120,000 kilometers (or 0.027 astronomical unit) away from the planetary center. The maximum mass of a moon keeping a stable orbit around the planet would be approximately 10 times Earth mass. With a speculated radius of 1.026 Jupiter radii. The calculated albedo of the planet is estimated at 0.79, while the gravitational influence (Hill sphere) is estimated at 11,470,000 km (0.076 AU)
Because Iota Horologii is younger than the Sun, the announcement of a protoplanetary disk caused speculation of this system still being active in debris bombardment.[1]
[edit] Discovery
The discovery of Iota Horologii b was the result of a long-term survey of forty solar twin stars that was begun in November 1992. The planet represents the first discovery of an extrasolar planet with an European Southern Observatory instrument, with the data found at the La Silla Observatory in Chile.
The Keplerian signal found the planet to have an orbital period of 320.1 days, indicative of an orbiting planet with minimum mass of 2.26 Jupiter masses. "With an eccentricity of 0.161 and a semi-major axis of 0.925 AU, this object moves in the most Earth-like orbit found so far among extrasolar planets."[1] Iota Horologii b was the first planet found by a team of planet hunters lead by Martin Kürster in the summer of 1998.[2]
[edit] In fiction
- Iota Cycle, novel by Russell Lutz. Iota Horologii is a setting for colonization and terraforming. It has six planets, the second, Asia, being Iota Horologii b. The planets are named after the continents of Earth, in order from closest to the star: Australia, Asia, Europe, Africa, America, and Antarctica.
- Outre Mer, novel by Michael Puttré. The earthlike moon Outre Mer orbits the gas giant Adonis, the second planet of Iota Horologii. It is populated by human refugees, descendants of adbuctees taken by the Greys, inhabitants of the systems of Zeta Reticuli. The world is also the home of the Duranni, an intelligent aboriginal species.
- Halo video game series. In the series, Soell is the traditional name given to Iota Horologii, the star that Threshold, Basis and Installation 04 orbit.
[edit] See also
[edit] References
- ^ Kürster et al. (2000). "An extrasolar giant planet in an Earth-like orbit. Precise radial velocities of the young star iota Horologii = HR 810". Astronomy and Astrophysics 353: L33 – L36.
- ^ Naef et al. (2001). "The CORALIE survey for southern extrasolar planets V. 3 new extrasolar planets". Astronomy and Astrophysics 375: 205–218.
