Kepler-22B is the first extra-solar planet or exoplanet, which is found in the Kepler space telescope in the habitable zone of its star. It is considered as a promising place to discover life. But at the distance of 600 light-years, this world may need more powerful telescopes for further investigation.
Kepler-22b is an extrasolar planet orbiting G-type star Kepler-22.
Kepler-22b is located about 600 light years from Earth in the constellation of Cygnus.
It was discovered by NASA’s Kepler Space Telescope in 2011 and was the primary celebrated transiting planet to orbit within the habitable zone of a Sun-like star.
Discovery and observation The planet’s first transit in front of its host star were observed on Kepler’s third day of scientific operations, on 12 May 2009.
You can also read our article “10 Earth-like planets could be our next home” for more information about most habitable planets.
The third transit was detected on 15 Dec 2010. Additional confirmation information was provided by the Spitzer Space Telescope and ground-based observations.
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On 5 Dec 2011, the confirmation of the existence of Kepler-22b was declared. Past transit dates Orbit. The only parameters of the planet’s orbit that are presently available are its period, which is concerning 290 days, and its inclination, which is approximately 90°, so that it transits the disk of its star as seen from Earth. No info is available concerning the shape of the planet’s orbit.
Many extrasolar planets are celebrated to move in highly elliptical orbits. It is solely known that its average orbital distance is at intervals its host star’s habitable zone.
If Kepler-22b has an extremely elongated orbit it’s going to well solely spend a little fraction of its time within this habitable zone, which might cause high-temperature differences on the planet and might make it inhospitable.
In order to obtain info concerning the shape of the planet’s orbit, other methods of planetary detection, such as the radial velocity method, need to be used. While such methods have been performed on the planet when its discovery, they need not, however, detected what the orbital eccentricity of the planet truly is, and have as of March 2012 solely set a higher limit on the mass of the planet. Physical characteristics Kepler-22b’s radius is roughly 2.4 times the radius of Earth.
It’s mass and surface composition stay unknown, with just some terribly rough estimates established: it’s but 124 Earth masses at the 3-sigma confidence limit, and fewer than 36 Earth masses at 1-sigma confidence.
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The adopted model in Kipping et al. does not reliably detect the mass, though the mass is below 52.8 Earth masses to 95% confidence.
Kepler-22b might be an “ocean-like” world. It might also be comparable to the water-rich planet GJ 1214 b although Kepler-22b, unlike GJ 1214 b, is in the habitable zone. An Earth-like composition is dominated resolute a minimum of 1-sigma uncertainty by velocity measurements of the system.
Kepler-22b is thus likely to have a more volatile-rich composition with a liquid or gaseous outer shell; this would make it similar to Kepler-11f, the smallest known gas planet.
“If it’s principally ocean with a little rocky core”, Natalie Batalha, one of the scientists on the project, speculated, “it’s not beyond the realm of possibility that life could exist in such an ocean”.
This chance of life has spurred SETI to perform analysis on high candidates for extraterrestrial intelligence. Climate and habitability The average distance from Kepler-22b to its host star Kepler-22 is about 15% less than the distance from Earth to the Sun but the luminosity of Kepler-22 is concerning 25th less than that of the Sun.
This combination of a shorter average distance from the star and a lower stellar luminosity is consistent with the moderate surface temperature at that distance if it is assumed that the surface isn’t subject to extreme greenhouse heating.
If Kepler-22b is found to move in an exceedingly highly elliptical orbit, its surface temperature will vary from a higher temperature when close to Kepler-22 to lower when farther away.
If the orbit is so extremely elliptical, then the temperature variance will be extreme.
Scientists will estimate potential surface conditions as follows: within the absence of an environment, its equilibrium temperature would be approximately −11°C.
If the atmosphere provides a greenhouse effect similar in magnitude to the one on Earth, it would have an average surface temperature of 22 °C. If the atmosphere has a greenhouse effect similar in magnitude to the one on Venus, it would have an average surface temperature of 460 °C.
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Recent estimates recommend Kepler-22b has over 95th chance of being placed within the empirical habitable zone defined by the recent Venus and early Mars limits, but less than a 5% chance of being located in the conservative habitable zone estimated from a 1D cloud-free radiative-convective model.
Limits on satellites The Hunt for Exomoons with Kepler project has studied the Kepler photometry of this planet for evidence of transit timing and duration variations that may be caused by an orbiting satellite.
Such variations were not found, ruling out the existence of satellites of Kepler-22b above 0.54 Earth masses at 95% confidence.
NASA’s Confirms Its initial Planet In Habitable Zone, Kepler discoveries: Kepler-22b: ‘a yearly orbit of 289 days’.