After eight years of trying, a group of researchers at Berkeley (California- USA) finally managed to photograph a Extrasolar planet that could be for the stronger, more similar to Earth than all those discovered so far. It is located just 25 light years from us and probably has a mass similar to that of Jupiter. The object orbiting the star Fomalhaut at a distance equivalent to about 4 times what there is between Neptune and our Sun, which is about 4 billion and a half kilometers. When the planet was given the name of Fomalhaut b, according to early indications, could be surrounded by a group of rings similar to those that Jupiter possessed before the material will thicken in the Galilean satellites known.
"Already in 2005 we advanced the hypothesis that the ring of dust surrounding the star could accommodate a large planet, as we noted a particularly devoid of material. This could mean that a planet had to himself aggregate objects that filled that space. Now, finally, we have visual proof that there really is a planet, "said Paul Kalas, head of research, which is published in Science.
In most cases Extrasolar Planets are not searched through photographs, because the instruments now in possession hardly able to identify them close to their stars, but through techniques that exploit the fall of light that they are causing to their star when they pass in front. Or through methods that detect changes in the trajectory of the stars around which orbit, following that of Attraction gravitational planets exert.
Attempts to photograph the planets were made only infrared telescopes pointing towards young stars hoping to observe planets in formation still hot. In the case of Fomalhaut b but has tried in visible light and so the result is considered exceptional. A chronicle of honor already in another case spot Gemini telescope in Hawaii had photographed a likely Extrasolar planet, but he has a mass of 8-9 times that of Jupiter and thus more closely to the "brown dwarf" (objects that are a middle ground between planets and stars) is not a true planet.
"Fomalhaut b is located within a band of dust so rich that it is very likely that it is mainly rocky, or at least have a solid nucleus very substantial," said Eugene Chiang, co-author of the research.
The hopes of finding life on the planet, however, are almost zero. Its star is home to only 200 million years and will live for no more than a billion years, because too little on the planet inneschino conditions to support life (our Sun is 4.5 billion years and will live for a equally long time). The short life of the star that makes it 16 times brighter than our Sun and that the light on the planet appears similar to that of our star that is observed by Neptune, although b Fomalhaut is at a distance by 4 times higher Its parent star.
In these days comes another discovery of planets extrasolari, which will be also published in Science. This is a real family of planets brought to light by the Gemini telescope. Thanks to this fact, researchers from the Lowell Observatory have revealed that around the star HR 8799, there are three planets that are about 60 million years. According to some estimates, they should have a mass of 7, 10 and 10 times that of Jupiter and have a diameter of between 20 and 30% above the giant planet.
To date Extrasolar Planets are discovered orbiting 322 and 276 stars. But there is to be sure, it was only the beginning.
(italian source: repubblica.it)