Extra-solar planets or exoplanets are planets located outside our solar system. When PSR1257 and PSR1257 + 12 B + 12 C (use uppercase for the first exoplanets discovered, as it was in force current terminology), and then 51 Pegasi b, the first exoplanet whose existence was confirmed, were discovered in the early 1990s, the success has been proclaimed as the most significant performance discovery in astronomy after Copernicus's heliocentric system.
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| 51 Pegasi b discoverry |
The allegations have created a tumult in the scientific world, reviving hopes of finding Earth-like planets, life forms probably outside the Solar System. Prior to these findings, the extrasolar planets were considered by astronomers known as non-existent, and their mere mention was fiction, so that no respectable scientist has not taken seriously until recently.
Since the advent of science exoplanetare study these celestial bodies evolved rapidly into a new branch of astronomy, cataloging more than 400 planets (30 of them documented in a single month, October 2009), only that many of them were in disappointingly, similar to the first: the hot gas giants orbiting close to their stars and revolutions taking only a few days.
The most plausible explanation for this is that the indirect method of detecting exoplanets is based on the hypothesis of the existence of massive objects with small orbital periods, which make them easy to identify. However, from time to time, with advanced technology and innovative methods, detection capability increases, so we have a few surprises:
The oldest planet
PSR B1620-26 b (found: May 30, 1993, state: July 10, 2003)
PSR B1620-26 b, nicknamed "Methuselah" after the famous biblical character who had lived nearly a thousand years, is the oldest exoplanet discovered with the age of 13 billion years. Considering that the universe itself does not exceed than 700 million years the leat, PSR B 1620 is likely to have even absolute record for the oldest existing planet.
Astronomical body was discovered in the center of what is called "globular cluster" of stars, cosmic entity made up of the first stars formed immediately after the Big Bang. And based on what we know about planet formation, they are born shortly after the star around which orbits, so if exoplanet's star is as old as the universe, the planet gives him detour is characterized by a similar age .
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| PSR B1620-26 b |
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| PSR B1620-26 b photo: exoplanetkyoto.org |
"Methuselah" was recognized as a planet only in 2003, confirming a sweet nectar dripped into the ears of planet hunters. The reason? If the planets could form as soon as the stars immediately after the Big Bang, also means that the universe is full of astronomical bodies waiting to be discovered.
The nearest exoplanet
Epsilon Eridani (Epsilon Eridani b, discovered on August 7, 2000)
It is situated at a distance of "only" ten light-years from Earth and is actually a system of planets, description employed and to define your own solar system. The name "Epsilon Eridani" stands for paternal star, or "sun" this "gear" cosmic, the composition of which is supposed to enter two worlds: one of them confirmed, Epsilon Eridani b, and the other not certified yet, Epsilon Eridani C.
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| Epsilon Eridani System is Remarkably Similar to Our Own photo: Sci-News.com |
Join all these form the nearest planetary system in the universe. The whole surrounding Epsilon Eridani is even two asteroid belts, one indoor, between Epsilon Eridani b and star, and the other outside, between EE b and e.e. c, plus a cosmic dust ring beyond the orbit of Epsilon Eridani c, resulting probably from the impact of two comets.
Exoplanets with most suns
Aquarii b (16 Nov 2003)
When it comes to planets, we are accustomed to viewing an image in which several such heavenly bodies revolve around the sun in an monostelar.
Well, it seems that, in fact, an impressive number - about 50% of cases - the stars we see in the night sky are star systems, or groups of two or more incandescent orbiting the common center their masses.
Naturally, the reason that our eyes perceive these compounds as single light dots is due to the huge distance that separates us from them. In the system there are five star 91 Aquarii.
In November 2003, it was discovered that a gas giant planet orbiting the star 91 Aquarii the main planet is named 91 Aquarii Ab so that it can be distinguished from stars in the system, leaving room for possible undiscovered planets in the same gear.
Gas giant is special because detection methods surrounded by stars exoplanets requires absolute precision - often futile anyway - so by the 91 Aquarii Ab is one of the few planets discovered in such conditions.
Infrared detector of NASA's Space Telescope Spitzer found substantial amounts of rock evaporated together with the solidified lava fragments, known as Tekt and is formed generally as a result of impacts from meteorites.
However, the existence of such material in a quantity enough to block the glow of a star indicates a greater impact, as only a planetary collision could be.
According to this discovery, interplanetary collisions are not so unusual a phenomenon in the universe, supporting it by default, and the widespread theory that the Earth's moon itself appeared as a result of a similar event in the distant past. Moreover, computer simulations have predicted the possibility of future collisions in our solar system sometime in the next three billion years.
Twin planet to Earth
Gliese 581g (discovered in September 2010)
Recently discovered Gliese 581g, a planet the size of Earth, located in the habitable zone of its star, could host liquid water can be a life environment. If suspicions were confirmed, I have to do with the planet most similar to Earth and also the first case of alien orb with potential for human habitat.
Successful discovery of Gliese 581g is based on 11 years of scrutinizing the cosmos made with the WM Observatory Keck in Hawaii. The performance started with the discovery astronomers red dwarf Gliese 581, two new planets orbit.
Among these, the most interesting turned Gliese 581g, with a mass three to four times that of Earth and a revolution period of only 37 days. Estimates indicate that its mass is probably about a solid planet with a definite surface and that it has sufficient gravitational force to maintain an atmosphere.
The planet is to its star, somehow, what is Terra Luna in that rotation around its axis of Gliese 581g coincinde to revolve the planet, so it is a hemisphere permanently facing light the other is forever steeped in gloom.
Researchers estimate that the average temperature of the outer body surface ranges between -31 and -12 degrees Celsius. Of course, absolute temperatures range from the mid from Star heat and cold on the dark surface.
The gravity of the surface of Gliese 581g may be similar or greater than that of the loose earth, such that a person would easily be able to move on two feet on the surface of the planet.
Super-Earth covered by lava
COROT-7b (found on 3 February 2009)
European astronomers discovered by COROT satellite, a Super Earth several times more massive than Earth, only 475 light years from Earth.
Researchers claim that the exoplanet, named COROT-Exo-7b is not yet even the most pleasant place to visit. Although at first glance, there is water on Exo-7b, this is a borderline state between gas and liquid due to the huge mass of lava that covers celestial body.
It is possible that the Exo-7b have been a frozen planet that has migrated through its own solar system, turning, upon heating, a huge water planet. Most likely, it was formed inside a gas giant, as appropriate Earth, Venus, Mercury and Mars. It is almost certain, however, that Exo-7b is in the same situation it was in the earth immediately after its formation, many experts believe.
The first planet photographed
Fomalhaut b (discovered on 13 November 2008)
Direct observation of exoplanets is so difficult that was compared with the pursuit of flying insects in the right of a reflector in a hazy day, from a distance of several kilometers. For this reason, the first image of a planet that is outside our solar system captured by Hubble, is paramount.
Called Fomalhaut b, exoplanet is the size of Jupiter, and a possible ring system orbiting the star Fomalhaut. Astronomers inferred its existence since 2005, based on gravitational forces in the area, but it is the first case in which they failed to achieve a proper picture.
Visibility on Fomalhaut b is hampered by a ring of dust surrounding the star that he owns.
The latter has an age of 200 million years and is 16 times brighter than the Sun. Astronomers have approximated it will explode into a billion years in age rather than for a star. Although performance Hubble planet Fomalhaut b would have remained hidden had it not been so wide orbit around its star.
SurvivorV391 Pegasi b (discovered in March 2007)
This gas giant was found orbiting a white dwarf - a sort of dead star - which means that at some point in the past, during the red giant phase of the star (a red giant is a large dying star, preceding phase transformation into white dwarf) planet must have reached the surface of the sun or even have them inside your body orbiting astronomical dying.
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| Planet Survivor photo: Science News for Students |
It is an event that is likely the planets of our solar system, including Earth, it is believed that our sun will enter the red giant phase sometime in the next five billion years, increasing its volume possible until assimilate orbits close to him, researchers believe that the sun could reach even to the orbit of Mars now.
Normally, many planets as "occupied" can fall apart, but others can keep the structure unchanged, as is the case of V391 Pegasi b, baptized, therefore, survivor. However, even if the earth will prove the same strength and survive in the sun become a red giant, its surface will be completely sterilized of huge temperatures.
Another gas giant "special" in the sense that its orbital plane aligns perfectly with our vision, so can be seen from Earth, the planet HD209458 b
Movement of "transition" of the planet through the right side to its star that we oriented afford to accurately calculate a size - by analyzing the amount of starlight blocked - and more importantly, to determine its atmospheric composition spectroscopy study interaction between radiation and matter (in this case, the interaction of gases and vapors in the atmosphere of the planet and its sun starlight).
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| Hubble measures atmospheric structure of extrasolar planet HD 209458b photo: ESA/Hubble |
With this method, researchers have detected the presence of sodium and, more recently, in October 2009, and that of water vapor, carbon dioxide and methane in the upper atmosphere of the planet. This is the second astronomical body which was found to possess organic compounds, HD 189733 b was the first planet discovered by humans which is characterized by it.
First 'Super-Earth'
Mu Arae c (discovered on 25 August 2004)
The planet's first "super-Earth" (or large rocky exoplanet) found, has brought researchers closer to discovering Earth-like planets outside the Solar System.
A "super-Earth" is defined as an exoplanet with mass between the Earth and the giant planets in our solar system. Why are these planets are considered to be "rock"? Weak gravitational force of an object the size of Earth materials tends to attract mainly massive, dense (rock and metal), and much less light materials such as gases, which are easily scattered radiation of astronomical phenomena such as stars, escape atmospheric or strong impacts with asteroids.
As this solid protoplanet increases, reaching a mass close to that of Jupiter's gravitational pull allows you to draw more objects on its surface and take captive the light gases, thus creating a spiral will turn in finally, another giant planet gas.
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