HD 80606b
| Exoplanet | List of exoplanets | |
|---|---|---|
 to scale with Jupiter |
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| Parent star | ||
| Star | HD 80606 | |
| Constellation | Ursa Major | |
| Right ascension | (α) | 09h 22m 37.5679s |
| Declination | (δ) | +50° 36′ 13.397″ |
| Apparent magnitude | (mV) | 8.93 |
| Distance | 190 ly (58 pc) |
|
| Spectral type | G5V | |
| Orbital elements | ||
| Semi-major axis | (a) | 0.453 ± 0.015AU (67.8 Gm) |
| 7.8 mas | ||
| Periastron | (q) | 0.0301 AU (4.50 Gm) |
| Apastron | (Q) | 0.876 AU (131 Gm) |
| Eccentricity | (e) | 0.9336 ± 0.0002 |
| Orbital period | (P) | 111.436 ± 0.003d (0.30509 y) |
| (2674.5 h) | ||
| Orbital speed | (υ) | 8.8–47.3km/s |
| Inclination | (i) | 89.285 ± 0.023° |
| Argument of periastron |
(ω) | 300.4977 ± 0.0045° |
| Time of periastron | (T0) | 2,454,424.857 ± 0.05JD |
| Time of transit | (Tt) | 2,454,876.344 ± 0.011JD |
| Time of eclipse | (Te) | 2,454,424.736 ± 0.003JD |
| Semi-amplitude | (K) | 472 ± 5m/s |
| Physical characteristics | ||
| Mass | (m) | 4.0 ± 0.3MJ |
| Radius | (r) | 0.921 ± 0.036RJ |
| Density | (ρ) | 4440 ± 240kg m−3 |
| Surface gravity | (g) | 9.6 g |
| Temperature | (T) | at periastron: 1500 K |
| Discovery information | ||
| Discovery date | 4 April 2001 | |
| Discoverer(s) | Geneva Extrasolar Planet Search | |
| Discovery method | Radial velocity | |
| Other detection methods | Orbital phase reflected light variations Transit (secondary) |
|
| Discovery site | Haute-Provence Observatory | |
| Discovery status | Published | |
| Other designations | ||
|
Struve 1341 B b, HIP 45982 b
|
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| Database references | ||
| Extrasolar Planets Encyclopaedia |
data | |
| SIMBAD | data | |
| Exoplanet Archive | data | |
| Open Exoplanet Catalogue | data | |
HD 80606 b (also Struve 1341 B b or HIP 45982 b) is an eccentric and hot Jupiter 190 light-years from the Sun in the constellation of Ursa Major. HD 80606 b was discovered orbiting the star Struve 1341 B in April 2001 by a team led by Michel Mayor and Didier Queloz. With a mass 4 times that of Jupiter, it is a gas giant. Because the planet transits the host star its radius can be determined using the transit method and was found to be slightly smaller than Jupiter's. Its density is slightly less than Earth's. It has an extremely eccentric orbit like a comet, with its orbit taking it very close to its star and then back out very far away from it every 111 days.
HD 80606 b has the most eccentric orbit of any known planet after HD 20782 b. Its eccentricity is 0.9336, comparable to Halley's Comet. The eccentricity may be a result of the Kozai mechanism, which would occur if the planet's orbit is significantly inclined to that of the binary stars. This interpretation is supported by measurements of the Rossiter–McLaughlin effect, which indicate that the planet's orbit may be significantly inclined (by approximately 50 degrees) to the rotational axis of the star, a configuration which would be expected if the Kozai mechanism were responsible for the orbit.
As a result of this high eccentricity, the planet's distance from its star varies from 0.03 to 0.88 AU. At apastron it would receive an insolation similar to that of Earth, while at periastron the insolation would be around 800 times greater, far more than that experienced by Mercury in the Solar System. In 2009, the eclipse of HD 80606 b by its parent star was detected, allowing measurements of the planet's temperature to be made as the planet passed through periastron. These measurements indicated that the temperature rose from around 800 K (500 °C / 1000 °F) to 1500 K (1200 °C / 2200 °F) in just 6 hours.
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