Sunday, June 17, 2012
The discovery of an exoplanet
A reacharger group of European astronomers has announced the discovery of an exoplanet particular. Is larger than Jupiter and may be gaseous, so it does not look like Earth. But what is its origin awareness. In fact, that distant world was not formed in our galaxy, but entered it, along with its star, about 9,000 million years. The finding is published this week in Science.
"The discovery is very exciting, says Rainer Klement, one of the authors of the study, for the first time, astronomers have detected a planetary system in a stellar group of extragalactic origin.Because of the enormous distances, yet we have no confirmed detections of planets in other galaxies. But this cosmic merger has brought an extragalactic planet within our reach. "
10,000 million years ago, there was a small galaxy very close to ours. It was much smaller than the Milky Way, but large enough to have several billion stars in it. Among its peers, our protagonist, HIP13004 star, had taken, from billions of years ago, a completely normal existence. The star shone from time immemorial, illuminating its attendant planets, and was coming to maturity.
But 9,000 million years ago everything changed. And that is the Milky Way galaxy, began to devour its smaller companion, the "Home of HIP13004, undoing literally" stealing "all their stars. Today, the remains of that ancient act of galactic cannibalism are still visible in our sky.
Indeed, HIP13004 and many of his colleagues is part of a group of stars, 2,000 light years away, which astronomers call the "Helmi stream". All of them, although at present are within the Milky Way, come from that old and missing galaxy.
Galactic cannibalism is not an isolated phenomenon. We know that during its long history, the Milky Way has swallowed up many smaller galaxies has been finding its way. And we know that at present the process of cannibalism is happening in other galaxies, as evidenced by the numerous (and spectacular) images obtained by telescopes, including Hubble.
Even the Milky Way, our home in space, will escape a similar fate. In the distant future, in fact, our own galaxy will collide and will merge with Andromeda, another giant of the same dimensions and is now the nearest neighbor of the Milky Way, two million light years away.
But let the planet. About HIP13004 astronomers have found a world, which have dubbed HIP13044b. This is a large planet with a size of at least 1.25 times that of Jupiter and, like its star, has not been formed in the Milky Way. In fact, this is the first extragalactic planet detected so far. He came to our galaxy accompanied by his star as their own "home" space was devoured by the Milky Way.
What's more, besides the "kidnapping" of its star, the wretched world has had to endure another catastrophe. And that is their star, far outweighed the Ecuador of its existence, and has already gone through the turbulent phase of expansion by passing all the stars that have exhausted their primary fuel, hydrogen. At such times, the stars become red giants and grow to several times their original size, swallowing often their entire planetary systems. Our own sun will also do the same within about 5,000 million years.
When the hydrogen runs out, the nuclear furnace of the center of the star turns off temporarily for lack of fuel. Without the explosive energy of stellar furnace, gravity, which attempts to compress the mass of the star, the crushed beyond repair, compressing it without hesitation. However, a compressed gas is also heated, and thus, as it tightens the severity, the temperature of the star also is increasing, reaching which is necessary for the combustion of other nuclear waste gases that are hydrogen and burned. When that happens, the star's nuclear furnace is turned back suddenly, and the entire star "bounces", swelling and a burning balloon to several times its original size.
One moment, certainly not convenient for any orbiting planets, which are likely to eventually absorb by the star itself? It has been estimated, for example, when the Sun enters the sudden expansion phase, its perimeter will grow to the orbit of Venus, which is the second planet in our system. When that happens, Mercury and Venus will be vaporized and literally swallowed by the Sun and Earth; if you have not suffered the same fate will be as close to the sun king that life will be impossible on the surface.
HIP130044 is today very close to its star. At its closest point, is only less than a stellar diameter away (or 0.055 times the distance from Earth to the Sun, which is 150 million km), and makes a complete orbit in only 16.2 days. The authors believe that the star has absorbed its possible inner planets and, before becoming a red giant, the orbit of the newfound world must have been much greater.
Therefore, the study is important HIP13044b. Because it can teach us much about the fate of our solar system, when the sun runs out of fuel and go through the process described above. The researchers say the finding may challenge our current understanding of the formation and survival of the planets. And, simply, the newly discovered HIP13044b should not be there.
"This discovery, says Johny Setiawan, who led the research is part of a larger study in which we systematically exoplanets orbiting stars near the end of his life. And this finding is particularly intriguing when we consider the future of distance our own solar system, when the Sun, as expected, becomes a red giant in about 5,000 million years. "
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