 An artist's impression of HD28185 b | |
| Discovery | |
|---|---|
| Discovered by | Santoset al. |
| Discovery site | La Silla Observatory |
| Discovery date | April 4, 2001[1] |
| Radial velocity (CORALIE) | |
| Orbital characteristics[2] | |
| 1.035+0.042 −0.046 AU | |
| Eccentricity | 0.055+0.004 −0.003 |
| 1.056 ± 0.0002years (385.704 ± 0.073 d) | |
| 2452262.394+3.714 −3.315 | |
| 356.596°+3.495° −3.155° | |
| Semi-amplitude | 163.657+0.653 −0.533 |
| Star | HD 28185 |
| Physical characteristics[2] | |
| Mass | ≥5.837+0.486 −0.510 MJ |
HD 28185 b is anextrasolar planet 128light-years away from Earth in theconstellation ofEridanus. The planet was discovered orbiting theSun-likestarHD 28185 in April 2001 as a part of theCORALIE survey for southern extrasolar planets, and its existence was independently confirmed by theMagellan Planet Search Survey in 2008.[3] HD 28185 b orbits its sun in a circular orbit that is at the inner edge of its star'shabitable zone.[4]
HD 28185 b was discovered by detecting small periodic variations in theradial velocity of its parent star caused by thegravitational attraction of the planet. This was achieved by measuring theDoppler shift of the star'sspectrum. In 2001 it was announced that HD 28185 exhibited a wobble along the line-of-sight with a period of 383 days, with anamplitude indicating aminimum mass 5.72 times that ofJupiter.[1][5]
HD 28185 b takes 1.04 years to orbit its parent star. Unlike most known long-period planets, the orbit of HD 28185 b has a loweccentricity, comparable to that ofMars in theSolar System.[6] The orbit lies entirely within its star's habitable zone.[4]
The amplitude of the radial velocity oscillations means that the planet has a mass at least 5.7 times that of Jupiter in the Solar System. However, the radial velocity method only yields a minimum value on the planet's mass, depending on the orbitalinclination to ourline-of-sight. Therefore, thetrue mass of the planet may be much greater than this lower limit.
Given the planet's high mass, it is most likely to be agas giant with no solid surface. Since the planet has only been detected indirectly through observations of the star, properties such as itsradius, composition, andtemperature are unknown. Periastron (0.959 AU), semimajor axis (1.031 AU) and apastron (1.102 AU) irradiances are 112%, 96.6% and 84.5% that of the Earth.[note 1]
Since HD 28185 b orbits in its star's habitable zone, some have speculated on the possibility of life on worlds in the HD 28185 system.[7] While it is unknown whether gas giants can support life, simulations of tidal interactions suggest that HD 28185 b could harbor Earth-masssatellites in orbit around it for many billions of years.[8] Such moons, if they exist, may be able to provide ahabitable environment, though it is unclear whether such satellites would form in the first place.[9] Additionally, a small planet in one of the gas giant'sTrojan points could survive in a habitable orbit for long periods.[10] The high mass of HD 28185 b, of over six Jupiter masses, actually makes either of these scenarios more likely than if the planet was about Jupiter's mass or less.
{{cite journal}}: CS1 maint: multiple names: authors list (link)
