An illustration of K2-33b. (Photo: NASA/JPL-Caltech)

Of all the far-away exoplanets that NASA has been finding with the Kepler telescope, some of the most important and fascinating are young planets, which can help scientists understand how planets form.

In a new Nature paper, a team of astronomers describes K2-33b, the youngest “fully formed” planet ever discovered. In a second paper, another team of scientists describe a young “hot Jupiter.”

Both planets orbit remarkably close to the their starts. K2-33b is 10 times closer to its star than Mercury is to ours—so close that its orbit is just 5 days long. Its age is estimated to be between 5 and 10 million years, which is nothing, for a planet.

The second young planet is orbiting a star that’s just 2 million years old, and again, it’s remarkably close in. It’s so close that it’s characterized as a “hot Jupiter”—which is basically what it sounds like, a planet like our Jupiter that’s closer to a star and, therefore, hotter.

The mystery of this planet is how it got so close to the star. As the Guardian explains, astronomers have previously thought a planet as big as this one could not form this close to a star—there’s just not enough material. Finding this planet adds evidence to the idea that planets like this one form further out and are pushed closer in.

Every day, we highlight one newly found object, curiosity or wonder. Discover something amazing? Tell us about it! Send your finds to sarah.laskow@atlasobscura.com.