Exoplanets Kepler-62 system
Two new planetary systems
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Updated April 20, 2013
Already in December 2011, NASA confirmed the discovery of the first planet in the "habitable zone" of its star. It was the exoplanet kepler-22b. In April 2013 two new planetary systems discovered Kepler-62 and Kepler-69. The Kepler-62 has five planets, 62b, 62c, 62d, 62e and 62f. The Kepler-69 system has two planets, 69b and 69c three super-Earths (Kepler-62e, 62f and 69c) which are in the "habitable zone" that is, they may contain liquid water. Kepler-62 is smaller and colder than the Sun system. Kepler-62f, 'rock composition' has a size only 40 percent larger than the Earth, and it is in the habitable zone of its star, it orbits in 267 days. Kepler-62e, has a size 60 percent larger than the Earth, and it also lies in the habitable zone of its star. However it orbits at the inner edge of the habitable zone in 122 days. The third planet, Kepler-69c, which we do not know the composition is 70 percent larger than the size of the Earth, its orbit of 242 days (as Venus) is in the habitable zone of the star Kepler-69, similar to our sun.
Since scientists know detect exoplanets, they are looking for worlds similar to our Earth because the ultimate goal is of course to find in the Universe, favorable conditions to the emergence of life to resolve the agonizing question that disturbs humanity since forever, "Are we alone in the universe?".
Each discovery brings us one step closer to that goal, it is now a question of time before we know if our galaxy is full of planets like Earth, or if we are a rarity. Kepler Space Telescope over a ton, went in the direction of the Milky Way, March 6, 2009 to search for extrasolar planets or exoplanets. The planets that the Kepler telescope will search, are small in size exohearth, 2 to 20 times the size of Earth, those that Corot space telescope in orbit since 2003, can not see.
"The Kepler spacecraft is proving to be a rock star of science," said John Grunsfeld, associate administrator of the Science Mission Directorate at NASA Headquarters in Washington. The Kepler space telescope observed simultaneously and continuously the brightness of more than 150,000 stars. "Kepler has brought renewed astronomical discoveries and we are making excellent progress to determine if planets like ours are the exception or the rule." said William Borucki, Kepler science principal investigator at the Research Center of NASA, in an article published in the journal "Science".
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Image: Relative sizes of all habitable planets discovered in the area in April 2013 alongside the Earth. From left to right: Kepler-22b, Kepler-69c, Kepler-62e, Kepler-62f, and the Earth (except Earth, which are images of artists). Credit image: NASA Ames / JPL-Caltech.
Kepler-62 planetary system
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The two planets in the habitable zone, Kepler-62e and 62f in orbit around Kepler-62 have three companions on orbits closer to their stars. Both are larger than the Earth and one has a size like Mars, these are Kepler-62b, Kepler-62c and Kepler-62d. They orbit around their star, respectively 5, 12, and 18 days, which makes them very hot and inhospitable to life as we know it on Earth. The five planets of system orbiting around Kepler-62 whose size measures only two-thirds the size of the sun with only one fifth of its brightness. The star Kepler-62, located 1200 light years from Earth in the constellation Lyra, is older than seven billion years, 2 billion more years older than the Sun. The Kepler-69 system belongs to the same class of stars than our sun, Type-G, it is 93 percent the size of the sun and 80 percent as luminous. It is located about 2700 light years from Earth in the constellation Cygnus. Kepler-69c is 70% larger than Earth, its orbit of 242 days (as Venus) is in the habitable zone of the star Kepler-69. His companion, known as Kepler-69b, is more than two times larger than Earth and rotates around its star in 13 days. "We know only one star that hosts a planet with life, the sun. Find a planet in the habitable zone around a star like our sun is an important milestone in efforts to find planets like Earth, "said Thomas Barclay, Kepler scientist at Bay Area Environmental Research Institute in Sonoma, California, and lead author of the discovery of Kepler-69 published in the Astrophysical Journal.
When a planet, "candidate for life," transits or passes in front of the star, from the Space Telescope, a percentage of light from the star is blocked. The decrease in brightness of starlight reveals the size of the transiting planet in front of its star. Using the transit method, Kepler has detected 2740 candidates. Using various analytical techniques, also aided by ground-based telescopes, 122 planets have been confirmed. At the beginning of the mission, Kepler telescope found that gas giant planets, "hot Jupiters", on very close orbits of their stars are easier to detect because of their size and very short orbital periods. To detect a planet like the Earth this takes three years because we must wait it accomplish three transits, necessary to be accepted as a planet candidate. It is probable that from 2013, three years after its first observations, the Kepler telescope floods scientists candidates to analyze. The Space Telescope Science Institute in Baltimore archives, hosts and distributes the Kepler science mission.
nota: A transit occurs when the planet passes between the star and the observer, at that time, the planet obscures some of the light from the star, producing a detectable periodic dimming. Kepler requires at least three transits to verify a signal as a planet.
Image: Kepler-62, this diagram compares the planets of the inner solar system to Kepler-62, a five-planet system, located about 1,200 light years from Earth. Scientists do not yet know if the planets located in the habitable zone of this system have a predominance rocky, gaseous or liquid fully composition. But it is possible that the atmosphere in these worlds that life exists.
Credit image: NASA Ames / JPL-Caltech .
The circumstellar habitable zone or ecosphere is a theoretical sphere surrounding a star where the temperature on the surface of planets in orbit, allow the appearance of liquid water. Liquid water is vital, because of its role in biochemical reactions. It has properties that are a catalyst for the production of chemicals necessary for life.
Frank Drake calculated the distance of this area in its equation of 1961. This equation takes into account the size, the brightness of the star and the luminosity of the sun.
A star that has 25% of the luminosity of the Sun will have a habitable zone centered at about 0.50 AU. A star that has twice the brightness of the sun, will have a habitable zone centered at 1.41 AU.
A habitable zone (ZH) does not mean that it contains within
it life, but there is a possibility depending on many other factors, that a terrestrial planet hosts life.
For example, Earth is home life, but the Moon, located in the same area, is sterile.
The planet candidate in the development of life, must be massive enough to prevent water from escaping. In addition, the space area is not a fixed area, it changes according to the temperature of the star, such as during their evolution the stars becoming brighter and more hot, the habitable area s logically away from the star. A planet will therefore remain as long as possible in this area, to develop all the molecules necessary for life form.
To determine the habitability of a planet, we must not look all conditions met our Earth, or no other planet in the universe might be harboring life, each planet is unique. Only the condition of having liquid water seems necessary, it is considered an essential element for a viable ecosystem because it helps tremendously transporting materials necessary for biochemical activity.
Water is a perfect item to dissolve the materials it stores very well the chemical elements.
So life may be present outside the habitable zone, just that there is liquid water on the surface or depth of a terrestrial planet, a source of energy and chemicals whose life needs to build its materials.
Astrobiologists believe that life forms may exist on other objects in our solar system like Europa, a Galilean moon of Jupiter at 500 million km from Earth. Europe is a covered ice ball the size of our Moon and has a sea of tens of km deep, liquid held by the energy of Jupiter's tidal forces. The friction caused by this stretching causes sufficient heat to maintain liquid water below the frozen surface.
The search for Exoplanets began in 1990.
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Image : The ecosphere or habitable zone of a solar system based on its brightness and its mass. Life can still be present outside the habitable zone, just that there's liquid water, a source of energy and chemicals whose life needs to build its materials.
Find the liquid water is finding the life ...