Kepler-452b (a planet occasionally claimed to be an Earth 2.0, or Earths cousin, depending on its characteristics; also known by its Kepler object of interest designation, KOI-7016.01) is an Earth-like exoplanet orbiting at the inner edge of the habitable zone of Kepler-452, a sunlike star. It is the only planet discovered in this system by Kepler.
The star Kepler-452b orbits are 6 billion years old, 1.5 billion years older than the Sun, and is in the phase of its life when its radius and luminosity are starting to increase, suggesting that the planet may have experienced or soon will experience, a runaway greenhouse effect in which its surface water boils away, similar to what happens on Venus. The world, known as Kepler 452b, is estimated to be slightly heavy, with five times the mass of the Earth, but it is receiving only 10% more heat and light than we receive from the Sun-like star that is similar to our own Sun.
The star it orbits, Kepler 452, in the constellation Cygnus, is about 20% brighter than Earth and is roughly two billion years old. Its star has a similar temperature to the Sun, but astronomers believe it is a little larger and brighter than the Sun. The newly discovered exoplanet, Kepler-452b, is at a much more energetic stage in its lifecycle than the sun; the star is roughly 10% larger and 20% brighter.
The increased energy output from its sun may be causing the newfound exoplanet Kepler-452b to warm and lose its oceans -- if the planet actually has any oceans at all -- due to evaporation, the consequent breakdown from UV light, and the loss of atmosphere. Similar to the way we have our sun, Kepler-452b orbits around a star called Kepler-452, 6 billion years old, a fairly long time for the sun in our solar system, 4.5 billion years old. If this is correct, stellar evolution theory will place its star at around 6 billion years old instead of the Sun's supposed age of 4.6 billion years.
This scenario probably will not happen to Kepler-452b, the newly discovered exoplanet, for another 500 million years, assuming estimates for the planet's size and the star's age are accurate, Jenkins said. While Kepler-452b may appear a tantalizing target for the upcoming NASA missions, it is highly unlikely humans ever will step foot on Kepler-452b, thanks to the 1,400 light-years it will take them to reach there.
Given that the Earth's oldest planet is 1,400 light-years away, we need far stronger telescopes than what we currently have to see the planet and understand what's going on there. For one thing, the fact that Earth's older is orbiting a G2-type star is enormously significant since all of the other Earth-sized planets we have found until now orbit stars that are cooler and smaller than our sun.
In addition to Kepler-452b, another 521 planet candidates -- including 12 candidates that are apparently between one and two times wider than Earth, orbiting within the habitable zone of their host stars -- were added to the missions watch list. Among the newest additions to the catalog of Kepler exoplanet candidates are a handful of smaller, likely rocky planets located in habitable zones -- distances from their stars allowing liquid water on their surfaces -- several smaller ones. The results are beginning to reveal that small, rocky planets are the most prevalent of all the types of planets in the Kepler catalog of exoplanet candidates, making up as much as 25%.
Astronomers have said at least one of these planets is in the Goldilocks Zone, meaning that the distance from its star is exactly right, making it neither too hot nor cold for life to exist. It is also in the habitable region, the ring of space which is a suitable distance from a planet's host star, such that it is not too hot and cold for life to exist -- what is called a Goldilocks zone.
Astronomers can manage this because, once per orbit, at least one of the planets passes in front of its star, just as seen from Earth.
For example, it takes At least one planet 385 Earth days to make a full orbit around its star, just slightly longer than an Earth year. If Kepler-452s star were closer to us and thus brighter, astronomers might measure the amount of wobble as it is pulled backward and forwards by planets orbiting around it. The Sun-like star Kepler-452 has an apparent magnitude of 13.426 -- that is, it appears to be brighter -- from Earth's perspective; thus, it is too faint to be seen by the naked eye.
The Kepler telescope has been watching around 150,000 stars for years, looking for telltale drops in brightness, which means that a planet is passing in front of a star and blocking part of its light.
NASA's prolific exoplanet-hunting satellite, Kepler, has been hunting for exoplanets by constantly looking at 150,000 stars and recording their brightness over a prolonged period. Kepler is a spacecraft that searches for planets orbiting other stars by measuring the dimming that the planets produce when passing between us and their host stars. The tracking has been followed up by observations at the ground level from telescopes across the United States, so we know a lot about the brightness of Earth's oldest host stars and about potential planets.
In 2009, NASA's Kepler spacecraft observed stars with a Kepler photometer. This instrument is used to spot transit events, where the planet passes in front of its host star and dims its host for a short, approximately regular period.
John Grunsfeld, an assistant administrator for Nasas Mission Directorate, said the new planet was the closest > Twin of Earth, or Earth 2.0, that Nasa had found in its data set to date. Kepler 452b has also been described as a Super-Earth since it has a higher mass than Earth but a significantly lower mass than the largest planets of our Solar System, such as Jupiter and Saturn, called gas giants. The Sun-like star is older than Earth -- suggesting that cosmic conditions for life may last longer.
One involves a rocky planet, only slightly larger than Earth, found in the habitable zone of its host star - in a type of orbit in which rocky planets can have liquid water.
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