Scientists have discovered an Earth-like planet that is only 11 light-years away — roughly three times the distance to the closest star system, Alpha Centauri. The planet could have temperate conditions on its surface that make it hospitable to life, scientists said.
The new planet, Ross 128b, is already drawing comparisons to Proxima b, an Earth-sized planet discovered in 2016 near Proxima Centauri, a star in the Alpha Centauri system.
Ross 128 b and Proxima b both orbit red dwarf stars, which are smaller and emit less heat than our own sun.
Proxima b's red dwarf, however, is much more active than Ross 128b's red dwarf. Since Ross 128b is less prone to exposure from solar flares, scientists believe it could be the more habitable of the two planets. But that depends on whether Ross 128b is in the so-called habitable zone of its parent star, which might mean liquid water could exist on its surface. Scientists aren't sure if that's the case yet.
"Many red dwarf stars, including Proxima Centauri, are subject to flares that occasionally bathe their orbiting planets in deadly ultraviolet and X-ray radiation," said the European Southern Observatory in a press release. "However, it seems that Ross 128 is a much quieter star, and so its planets may be the closest-known, comfortable abode for possible life."
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Ross 128b orbits its star every 9.9 days. Because the red dwarf emits less energy, Ross 128b receives only a third more energy from its star than Earth does from our own sun. Scientists estimate the equilibrium temperature of Ross 128b is somewhere between minus 60 degrees and 20 degrees above zero Celsius (minus 76 degrees and 68 degrees above zero Fahrenheit.)
Scientists found the planet using ESO's High Accuracy Radial velocity Planet Searcher (HARPS), located at La Silla Observatory in Chile. HARPS is one of the top planet hunters. It detects worlds through their gravitational pulls on stars. ESO plans to do follow-up observations with the Extremely Large Telescope, which is under construction and will see "first light" around 2024. The E-ELT possibly could spot oxygen — or other key molecules for life — in planetary atmospheres.
"Although it is currently 11 light-years from Earth, Ross 128 is moving towards us and is expected to become our nearest stellar neighbor in just 79,000 years — a blink of the eye in cosmic terms," ESO said. "Ross 128b will by then take the crown from Proxima b and become the closest exoplanet to Earth."
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