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Scientists used to wonder how common planets were throughout the universe, and at present nosotros know. They're extremely common. They're so common, in fact, it'south possible just to notice another 1 while you're trying to gather data on the one you already knew about. That's what happened when astronomers recently turned their attention to the star K2-18. They found a bonus planet.

The first exoplanet around this star, dubbed K2-18b, was discovered in 2022 by the Kepler Space Observatory. This musical instrument got a new lease on life when NASA engineers managed to recoup for the failure of its reaction wheels. It couldn't maintain orientation equally well as earlier, but it's "K2" stage still immune it to spot many exoplanets like K2-18b. Kepler uses the transit method to spot planets — when a globe passes in front of its host star, there's a small-scale drib in light. That's plenty to strongly advise a planet, just astronomers ever demand to follow up.

In the case of K2-18b, astronomers began observing information technology with the European Southern Observatory's planet-hunting HARPS instrument, which is part of the 3.half-dozen-meter telescope in the La Silla Observatory. It appeared to exist a super-Globe, a rocky planet more than massive than Earth, but Kepler couldn't tell us for sure. HARPS allowed the team to rail K2-18's radial velocity as K2-18b orbited it. These fluctuations allowed the team to determine the planet is in the habitable zone of the star and is probably composed of either rock or water and ice. Either fashion, there's some possibility it could support life.

The HARPS instrument.

While monitoring K2-18b, the team picked up some other signal that Kepler missed. It turned out to be another planet much closer to the star. This planet, now known as K2-18c, also looks like a super-Earth. All the same, information technology'south so close to the star that its temperature exceeds the boiling point of water. That makes information technology a poor candidate for life as we know information technology.

Information technology's remarkable we've been able to learn so much virtually a solar system more than 111 light years away, but this is only the beginning. Scientists are excited to see more planets orbiting red dwarf stars like K2-18. Some other of import exoplanet finds have been orbiting cherry dwarfs, similar the one right next door in the Proxima Centauri system. Not only are these stars plentiful and long-lived, only they're also good targets for study with the upcoming James Webb Telescope. That instrument should exist online in 2022.