Possible Scene from a Moon of the Extrasolar Jupiter-like Planet, HD23079
This is a possible scene from a moon orbiting the extra-solar planet in orbit around the star HD23079. The planet is about three times the mass of Jupiter and orbits the star in 628 days, with a nearly circular orbit of one and a half times the Earth-Sun distance (almost the same as that of Mars).
The star HD 23079 is a 7th magnitude star in the southern constellation Horologium, and is slightly brighter and hotter than our own Sun. The similarity of the appearance of the extra-solar planet to that of Jupiter arises because it has a similar mass. The possible existence of the moons been inferred from our knowledge of the planets in our own Solar System and from theories of planetary formation - they have not actually been detected.
Eight new planets have been discovered circling nearby stars, so-called extra-solar planets, and three of these are Jupiter-sized planets travelling in circular orbits similar to that of Earth and Mars in our own Solar System. The majority of extra-solar planets found previously, some 66, have eccentric orbits. These new findings strengthen the likelihood of finding an extra-solar 'sibling' to planet Earth in the future.
The discovery was made by a team of British astronomers using the 3.9m Anglo-Australian Telescope [AAT] in New South Wales, Australia, in partnership with colleagues from the US and Belgium. Two other telescopes were used in the collaborative research programme including the 10m Keck telescope in Hawaii, and the 3m Lick telescope in California to search the nearest 1,200 stars for planets.
The three planets found with Solar System-like orbits are circling the star HD23079 and HD4208. These planets constitute a new class of giant planets with orbits similar to that of Earth and Mars in the Solar System. The reason why astronomers are only just beginning to find such planets is that they lie far from their parent stars and take longer to orbit, requiring more precise measurements over a longer observing period.
The 8 new planets range in mass from 0.8 to 10 times the mass of Jupiter, the largest planet in the Solar System. These planets have orbital periods between 6 days and 6 years. They orbit their stars at distances ranging from about 0.07 to 3.5 times the Earth-Sun distance. The Keck Planet Search found 5 of the new objects and the Anglo-Australian Planet Search found 3.
The long-term goal of this programme is the detection of Solar System-analogs, Jupiter-like planets in Jupiter-like orbits. The discovery of such planets within the next decade will help astronomers assess the Solar System's place in the galaxy and whether planetary systems like our own are common or rare.
The first extrasolar planet ever discovered was found by a Swiss team in 1995. With the new planets announced today a total 74 extra-solar planets have now been discovered. NASA
