Researchers have found an exo-planet, dubbed KB200414Lb, orbiting a white dwarf star that has already completed its lifecycle. This finding suggests a scenario similar to Earth’s fate about 8 billion years from now.
In about 5 billion years, our own sun is expected to burn out into a white dwarf after expanding into a red giant, a phase that will consume Mercury and Venus, and potentially Earth and Mars. If Earth survives this transformation, it could eventually resemble KMT-2020-BLG-0414, drifting further from the remnants of our dying star.
KB200414Lb is about 1.9 times the mass of Earth and is likely a rocky planet. The findings, published in Nature Astronomy, suggest that the planet orbits the white dwarf at a distance of approximately 2.1 astronomical units (au). This discovery indicates that terrestrial planets born in regions further from their host stars may survive the chaotic red-giant phase that precedes the formation of a white dwarf.
Lead author Keming Zhang, an astronomer at the University of California, San Diego, stated, “We do not currently have a consensus on whether Earth could avoid being engulfed by the red giant sun in 6 billion years. In any case, Earth will only be habitable for another billion years, as the oceans will vaporize due to the runaway greenhouse effect-long before the risk of being swallowed by the red giant arises.”
KMT-2020-BLG-0414 was first detected in 2020 when it temporarily blocked the light of a more distant star, located 25,000 light-years away. This gravitational lensing effect made the distant planet detectable to astronomers.
