Kepler-452b

Mass, radius and temperature Kepler-452b has a probable mass five times that of Earth, and its surface gravity is nearly twice as much as Earth's, though calculations of mass for exoplanets are only rough estimates. Its radius is 50% larger than Earth's, and lies within the conservative habitable zone of its parent star. It has an equilibrium temperature of , a little warmer than Earth. Host star The host star, Kepler-452, is a G-type and has about the same mass as the sun, only 3.7% more massive and 11% larger. It has a surface temperature of 5757 K, nearly the same as the Sun, which has a surface temperature of 5778 K. The star's age is estimated to be about 6 billion years old, about 1.5 billion years older than the Sun, which is estimated to have existed for 4.6 billion years. Kepler-452b has been in Kepler-452's habitable zone for most of its existence, a duration just over six billion years. From the surface of Kepler-452b, its star would look almost identical to the Sun as viewed from the Earth. The star's apparent magnitude, or how bright it appears from Earth's perspective, is 13.426; therefore, it is too dim to be seen with the naked eye. Orbit Kepler-452b orbits its host star with an orbital period of 385 days and an orbital radius of about 1.04 AU, nearly the same as Earth's (1 AU). Kepler-452b is most likely not tidally locked and has a circular orbit. Its host star, Kepler-452, is about 20% more luminous than the Sun (L = 1.2 ). ==Potential habitability==

It is not known if Kepler-452b is a rocky planet It is not clear if Kepler-452b offers a habitable environment. It orbits a G2V-type star, like the Sun, which is 20% more luminous, with nearly the same temperature and mass. "Delayed" runaway greenhouse effect Due to the planet Kepler-452b being 50 percent bigger in terms of size, it is likely to have an estimated mass of 5 , which could allow it to hold on to any oceans it may have for a longer period, preventing Kepler-452b from succumbing to runaway greenhouse effect for another 500 million years. This could allow any potential life on the surface to inhabit the planet for another 500–900 million years before the habitable zone is pushed beyond Kepler-452b's orbit. ==Discovery and follow-up studies==

In 2009, NASA's Kepler space telescope was observing stars on its photometer, the instrument it uses to detect transit events, in which a planet crosses in front of and dims its host star for a brief and roughly regular time. In this last test, Kepler observed stars in the Kepler Input Catalog, including Kepler-452; the preliminary light curves were sent to the Kepler science team for analysis, who chose obvious planetary companions from the bunch for follow-up by other telescopes. Observations for the potential exoplanet candidates took place between 13 May 2009 and 17 March 2012. Kepler-452b exhibited a transit that occurred roughly every 385 days, and it was eventually concluded that a planetary body was responsible. The discovery was announced by NASA on 23 July 2015. , the probability of a false positive detection has been estimated at less than 1%, strengthening the existence of Kepler-452b. SETI targeting Scientists with the SETI Institute (Search for Extraterrestrial Intelligence Institute) have already begun targeting Kepler-452b, the first near-Earth-size world found in the habitable zone of a Sun-like star. SETI Institute researchers are using the Allen Telescope Array, a collection of 6-meter (20 feet) telescopes in the Cascade Mountains of California, to scan for radio transmissions from Kepler-452b. As of July 2015, the array has scanned the exoplanet on over 2 billion frequency bands, with no result, meaning that any sentient alien life have not discovered radio or do not exist. The telescopes will continue to scan over a total of 9 billion channels, searching for alien radio analysis. ==Observation and exploration==

Kepler-452b is from Earth. The fastest current spacecraft, the New Horizons uncrewed probe that passed Pluto in July 2015, travels at just . At that speed, it would take a spacecraft about 26 million years to reach Kepler-452b from Earth, if it were going in that direction. ==Gallery==

{{Gallery |align=center |width=450 ==See also==