10mn-year-old ‘newborn’: Youngest-ever exoplanet discovered, may hold key to planet formation

K2-33b, shown in this illustration, is one of the youngest exoplanets detected to date. It makes a complete orbit around its star in about five days. © NASA / JPL-Caltech
Scientists have discovered the youngest-ever fully formed exoplanet which, by planet standards, is just “an infant.” Analysis of the space body may hold the key to understanding processes that led to Earth’s formation, researchers say.

The ‘baby’ planet, named K2-33b, was detected by NASA's Kepler Space Telescope and its extended K2 mission, as well as the W. M. Keck Observatory on Mauna Kea, Hawaii, the US space agency said

K2-33b is slightly larger than Neptune and is considered an exoplanet as it orbits a star outside our solar system.

The age of the planet is relatively young – some 5 to 10 million years old, according to researchers.

© NASA / JPL-Caltech

"Our Earth is roughly 4.5 billion years old," said Trevor David of Caltech in Pasadena, lead author of the study on the planet. "By comparison, the planet K2-33b is very young. You might think of it as an infant."

The infant planet could prove useful to scientists, as by analyzing its structure and development they may be able to understand how all planets are formed. Though astronomers have discovered roughly 3,000 exoplanets so far, nearly all of them are more advanced in years than the latest find.

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“For astronomers, attempting to understand the life cycles of planetary systems using existing examples is like trying to learn how people grow from babies to children to teenagers, by only studying adults,” NASA said.

According to Erik Petigura from Caltech university, “the newborn planet will help us better understand how planets form, which is important for understanding the processes that led to the formation of Earth.”

NASA's Spitzer Space Telescope showed that the planet's host star is surrounded by a “thin disk of planetary debris,” NASA said, adding that this was an indication that the planet-formation phase “is wrapping up.” 
“Planets form out of thick disks of gas and dust, called protoplanetary disks, that surround young stars,” NASA added.

"Initially, this material may obscure any forming planets, but after a few million years, the dust starts to dissipate," said co-author Anne Marie Cody, a NASA Postdoctoral Program fellow at NASA's Ames Research Center in California's Silicon Valley. "It is during this time window that we can begin to detect the signatures of youthful planets with K2."

The baby exoplanet is also very close to its star.

“The planet is nearly 10 times closer to its star than Mercury is to our sun, making it hot. While numerous older exoplanets have been found orbiting very tightly to their stars, astronomers have long struggled to understand how more massive planets like this one wind up in such small orbits,” NASA said.

So it’s hard to say why K2-33b, a young planet, is very close to its star as theories suggest that it takes hundreds of millions of years to bring a planet from a more distant orbit into a close one.