The exoplanet most often referred to as Earth's "duplicate" is Kepler-452b.
Kepler-452b, discovered by the Kepler Space Telescope, orbits a star similar to our Sun. Here's a breakdown of why it earns this distinction:
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Orbital Characteristics: It orbits its star, Kepler-452, in 385 days, very close to Earth's 365-day year. The orbital radius is also similar to Earth's, at about 1.04 AU (Astronomical Units, where 1 AU is the distance from Earth to the Sun).
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Host Star Similarity: Kepler-452 is a G-type star, like our Sun, although it's about 20% more luminous.
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Potential Habitability: While its size is estimated to be larger than Earth (about 1.6 times the radius), placing it in the super-Earth category, it is located in the habitable zone of its star. This means it could potentially support liquid water on its surface, a key ingredient for life as we know it.
However, it's important to note some crucial differences:
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Age: The Kepler-452 system is significantly older than our solar system. This means Kepler-452b has had considerably more time to evolve, which could have resulted in a vastly different environment.
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Known Details: We do not know for certain if Kepler-452b has a rocky composition, an atmosphere, or liquid water.
Therefore, while Kepler-452b is often called Earth's "duplicate" or "cousin," it's more accurate to say it's one of the most Earth-like planets we've found to date, based on its orbital characteristics and the type of star it orbits. More studies and advanced observation tools are needed to confirm its true nature and potential for habitability.
