| Discovery | |
|---|---|
| Discovered by | Moutouet al.[1] |
| Discovery site | La Silla Observatory |
| Discovery date | October 26, 2008 |
| Doppler spectroscopy (HARPS) | |
| Orbital characteristics | |
| 1.28 ± 0.01 AU (191,500,000 ± 1,500,000 km) | |
| Eccentricity | 0.34 ± 0.021 |
| 499.4 ± 3.6d 1.367 ± 0.010y | |
Averageorbital speed | 28.0 |
| 2,454,502 ± 4.1 | |
| 308.2 ± 2.4 | |
| Star | HD 153950 |
HD 153950 b, also known asTrimobe, is anextrasolar planet located approximately 162light-years away. This planet was discovered on October 26, 2008 by Moutouet al. using theHARPS spectrograph on ESO's 3.6 meter telescope installed atLa Silla Observatory inAtacama Desert,Chile.[1]
The planet HD 153950 b is namedTrimobe. The name was selected in theNameExoWorlds campaign byMadagascar, during the 100th anniversary of theIAU. Trimobe is a richogre fromMalagasy tales.[2][3]
HD 153950 b is a Jupiter-size exoplanet. The estimatedminimum mass is 2.73 times themass of Jupiter. The planet has been found to orbit its host star every 500 days at a distance of 1.28AU, which is approximately 28% more of themean distance between the Sun and the Earth. HD 153950 b has a mildly elliptical orbit, given itsorbital eccentricity of 0.34.[4]
The temperature of the exoplanet is likely to vary during its orbit, temperatures would likely range from 275–375 K (2–102 °C; 35–215 °F) as it approaches itsperiastron/apastron of its orbit. This would also likely apply to a potentially habitable hypothetical moon orbiting the gas giant exoplanet (seebelow).
HD 153950 is anF-type star with amass that is 1.13 times the mass of the Sun and a size that is 1.34 times theradius of the Sun. In other words, it is slightly more massive and slightly larger than the Sun is. With aneffective temperature of 6076K, HD 205739 is also hotter than the Sun, although it is younger, at an estimated age of 4.3 billion years, 250–300 million years younger than the Sun.[4] The star is almost the same as the Sun in terms of metal; its measuredmetallicity is [Fe/H] = -0.01.[4] HD 153950 cannot be seen from Earth with thenaked eye because the star has anapparent magnitude (V) of 7.39.[4]
HD 153950 b is located within thehabitable zone of its star. The exoplanet, with a mass of 2.73MJ, is too massive to be rocky, and because of this the planet itself is not expected to habitable. However, based on a probable 10−4 fraction of the planet mass as a satellite,[5] it may have a large enough moon with a sufficient atmosphere and pressure, and liquid water at its surface, potentially making it habitable.[6] On the other hand, this mass can be distributed into many small satellites as well.
HD 153950's designation is from theHenry Draper catalogue. The star was also observed byHipparcos, which released its catalogue in 1997. The observations that led to the discovery of the planet HD 153950 b started when theN2K Consortium started an extended search for planets around 300 stars not usually targeted byDoppler spectroscopy surveys. In the case of HD 153950, the star was observed using telescopes at theLa Silla Observatory in Chile.
