sábado, 7 de abril de 2012

Beta Pictoris --Are Exotic New Planets Orbiting this Massive Star?


The dense clouds of carbon enveloping a nearby massive star, Beta Pictoris, hint that the star may be aggregating new planets, according to a past study led by Aki Roberage of the NASA Goddard Space Flight Center. Only 12 million years old, the 'baby star' Beta Pictoris is located about 70 light-years away towards the constellation Pictor (the Painter).

Goddard's Marc Kucher said "If carbon-rich worlds are forming in Beta Pictoris, they might be covered with tar and smog, with mountains made of giant diamonds...Life on such a planet is not implausible, but it would certainly be exotic."
In November of 2008, a team of French astronomers using ESO's Very Large Telescope have discovered an object located very close to the star Beta Pictoris, and which apparently lies inside its disc. With a projected distance from the star of only 8 times the Earth-Sun distance, this object is most likely the giant planet suspected from the peculiar shape of the disc and the previously observed infall of comets onto the star. It would then be the first image of a planet that is as close to its host star as Saturn is to the Sun.
Astronomers have long suspected that the young, 12-million-year-old star hosts a massive planet, since it is surrounded by a dusty disc of debris thought to be created by the collision of rocky bodies and infalling comets.
Evidence for such a planet grew stronger in 2006, when astronomers reported finding what appeared to be a second, smaller dusty disc around the star that was tilted slightly with respect to the main disc. It may have formed after a planet between 1 and 20 times the mass of Jupiter was thrown out of the main disc by gravitational interactions with other bodies there.
French astronomers say they may have spotted the suspected planet by reanalysing infrared observations of the star first made in 2003 with the Very Large Telescope in Chile. An adaptive optics system, which uses a shape-shifting mirror to offset turbulence in the atmosphere, was used to take the images.
Earlier observations showed a warp of the disc, a secondary inclined disc and infalling comets onto the star. "These are indirect, but tell-tale signs that strongly suggest the presence of a massive planet lying between 5 and 10 times the mean Earth-Sun distance from its host star," says team leader Anne-Marie Lagrange of Grenoble Observatory in France . "However, probing the very inner region of the disc, so close to the glowing star, is a most challenging task.We were able to achieve this after a precise and drastic selection of the best images recorded during our observations."
The team found a point-like glow around the star that might be a planet weighing about 8 Jupiters. The object appears to lie about as far from its star as Saturn does to the Sun - or about 8 astronomical units (where 1 AU is the Earth-Sun distance), closer to its star than any other extrasolar planet ever imaged.
"We cannot rule out definitively . . . that the candidate companion could be a foreground or background object," said team member Gael Chauvin. "To eliminate this very small possibility, we will need to make new observations that confirm the nature of the discovery."
Source: The Daily Galaxy - newsciemtist and eso.org 

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