Produced by: Mohsin Shaikh
HD 20794 was first thought to host three planets, but one was later dismissed. However, astronomers uncovered a new contender—HD 20794 d—potentially orbiting in the star’s habitable zone, reigniting the search for alien life.
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After years of analysis, University of Oxford astronomer Dr. Michael Cretignier confirmed HD 20794 d’s existence using advanced spectrographs. The discovery was once too faint to trust, but new data finally proved it real.
Credit: University of Oxford
With a mass 5.8 times that of Earth, HD 20794 d falls into the "super-Earth" category. Unlike Mars, which lost its atmosphere, this planet likely retains a thick one, possibly creating stable conditions for liquid water.
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The planet’s orbit swings between Venus-like proximity and Mars-like distance, triggering dramatic temperature shifts. If it has an Earth-like tilt, one hemisphere may endure extreme weather while the other remains stable.
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Unlike Proxima b’s violent host star, HD 20794 d orbits a calm, Sun-like star. This stability makes it less likely to have lost its atmosphere to stellar radiation, boosting its potential to support life.
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The planet doesn’t pass in front of its star from our perspective, ruling out JWST's usual atmospheric detection methods. However, upcoming telescopes like the Extremely Large Telescope could still reveal its secrets.
At just 20 light-years away, HD 20794 d is closer than TRAPPIST-1 or LHS 1140 b. This proximity makes it one of the best targets for future space missions seeking biosignatures beyond our Solar System.
Scientists can't agree on the age of its host star—some estimates suggest it’s slightly older than the Sun, while others claim it’s twice as ancient. This discrepancy could impact our understanding of planet formation.
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New telescopes could soon reveal HD 20794 d’s atmospheric composition and climate. If signs of life exist, this planet might become one of the most significant exoplanet discoveries in history.
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