Here is another example of a Gas Giant formed near the star Vega and migrating out ward. This is the second declared starsystem similar to our own in planetary configuration Vis; gas giants:
Unmasking Vega: Solar System Like Ours Emerges
By Robert Roy Britt
Senior Science Writer
posted: 06:03 am ET
08 December 2003
One of the closest and brightest stars in the sky appears to harbor a very familiar looking solar system, a young echo of our own complete with similar planets and an outer belt of colliding comets.
Vega is easily visible in the evening without a telescope. It is young, just 350 million years old compared to our Sun, which is 4.6 billion years old.
Vega is surrounded by an interesting dusty ring, which astronomers found in the early 1980s. It was the first discovery of a disk of material around another star. In the Carl Sagan's 1985 book "Contact," later a movie, Vega is the fictional source of radio transmissions.
Ever since, researchers have seen more and more signatures of planet formation in the Vega dust ring. They peer through the dust now with high-powered, high-altitude telescopes. It is like unwrapping Christmas presents to reveal the mysteries inside.
New computer modeling suggest the star is indeed spawning a solar system much like our own. Time, however, is not on Vega's side.
A team of astronomers at the UK's Royal Observatory say clumps of dust in the disk-like ring can best be explained by a Neptune-sized planet orbiting Vega at about twice the distance Neptune is from our Sun. That configuration, the researchers say, allows plenty of room for rocky planets like Earth to develop closer to the star.
The work was led by Mark Wyatt at the observatory's Astronomy Technology Center.
Neptune's twin
The modeling suggests the Neptune-like planet formed much closer to Vega than its current position. As it moved outward over some 56 million years, it swept comet-like objects with it, creating the clumpy disk seen today. A similar scenario is thought to have unfolded in our own solar system. A separate recent study showed how the migration of Neptune might be responsible for a population of icy objects, called the Kuiper Belt, beyond Neptune.
Wyatt told SPACE.com that the comets around Vega, according to this scenario, collide and create the dust that's been observed.
The dust does not represent a conventional "protoplanetary disk" that is left over when a star is born, he said. In fact, the absence of dust nearer to Vega -- like a hole in a donut -- suggests other planets already formed there. Vega's dusty ring, on the outskirts of its gravitational influence, is a second-generation phenomenon, a product of planet and comet evolution rather than the seeds of their birth.
The similarity of the apparent evolution of the outer regions of Vega's environment and that around our Sun "suggests that the two systems may have formed and evolved in a similar way, and so Vega may also have planets inside the orbit of the Neptune-like planet," Wyatt said.
A Jupiter-sized planet could lurk there, in an orbit similar to Jupiter, he said.
Wyatt's team did not analyze whether an Earth-like planet might exist. However, he said, "based on this model, nothing would prevent such a planet forming."
Creative techniques might allow astronomers to make an image of the Neptune-sized planet, if it exists, Wyatt said. But the task, involving blocking out the overpowering light of Vega, won't be easy.
Planets abound
Vega is not the only young star thought to have a developing planetary system. Fomalhaut, also nearby and the 17th brightest star in our sky, appears to have a Saturn-sized planet and also looks like an early version of our solar system.
And more than 100 planets have been found around more mature stars. Many of these systems are configured differently, however, with a huge Jupiter-mass planet circling very close to the star. No close-in terrestrial planets could survive such a setup.
A handful of mature systems do look like they could support habitable planets. One, with a Jupiter-sized planet in a Jupiter-like orbit, was found this year. A similar system discovered in 2002 was shown, mathematically, to be capable of supporting an Earth-like planet.
The new model for Vega is explained in the Dec. 1 issue the Astrophysical Journal. It is based on observations by the SCUBA camera on the James Clerk Maxwell Telescope in Hawaii. The dust was observed in the submillimeter region of the electromagnetic spectrum, at the border between far-infrared and short-wavelength radio emissions.
Running out of time
There is one significant difference between Vega's system and the one we live in: Unlike the Sun, which has at least a billion years to go, and probably more, before it begins to swell dangerously, Vega won't last long.
"Because it is some three times more massive than the Sun, [Vega] has just 650 million years of main sequence lifetime left," Wyatt said. "It will never be truly Sunlike."
This time limit makes it less likely that life will ever develop around Vega.
At about 25 light-years distance, Vega is the fifth brightest star in Earth's night sky. It is 58 times more luminous than the Sun. Anyone can find it with the help of a simple star chart. It is high in the West as darkness falls and sets in the Northwest around 10 p.m. at mid-northern latitudes.
This article is part of SPACE.com's weekly Mystery Monday series.
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