Astronomers discover youngest exoplanet to date
Astronomers havedetected the youngest exoplanet ever discovered, orbiting incrediblyclose to a distant star. The discovery of the infant planet, known asK2-33b, could allow astronomers to gain a clearer understanding ofthe earlier stages of planetary formation.
Prolific planet-huntingtelescopes such as Kepler and Hubble have identified over 3,000 alienworlds orbiting far-flung stars. The vast majority of theseexoplanets are discovered around stars that formed over a billionyears ago, meaning that the planets themselves are generally in themid-late stages of their lives.
Whilst the study ofthese exoplanets has revealed a great deal regarding their evolution,the relative absence of youthful planets such as K2-33b has preventedastronomers from unravelling many of the mysteries that persistregarding the early stages of planetary life cycles.
K2-33b was firstdetected as a periodic dip in light from its parent star, created asthe exoplanet passed between the stellar body and the Kepler Space Telescope. Follow up observations by the W. M. Keck Observatory,Hawaii, and infrared data collected by the Spitzer Space Telescopeconfirmedthat the system still plays host to a depleted protoplanetary disk,meaning that planetary formation had, at least in astronomical terms,only just concluded.
"Our Earth isroughly 4.5 billion years old," states Trevor David of Caltechin Pasadena, lead author of a study on the discovery. "Bycomparison, the planet K2-33b is very young. You might think of it asan infant." David is a graduate student working with astronomerLynne Hillenbrand, also of Caltech.
It is estimated thatK2-33b, which is believed to be slightly larger than Neptune, isbetween 5-10 million years old, making it the youngest exoplanetdiscovered to date. Data collected by the Earth and space-boundobservatories revealed that the exoplanet orbits very close to itsparent star, a characteristic that does not conform with currenttheories on planetary formation.
Ordinarily, it isthought that a body as massive and young as K2-33b should form in afairly distant orbit from its parent star, yet the newly discoveredexoplanet was observed 10 times closer than Mercury orbits from ourSun. Astronomers are at a loss to explain the unusual orbit.
Much older planets hadbeen observed in ultra-close orbits, but the migration process isthought to have taken hundreds of millions of years, and so could notexplain the orbit traversed by K2-33b. It is therefore possible thatthe planet was simply created in its current orbit through someprocess unaccounted for by the current models for planetaryformation.
A paper on the findingshas been published online in the journal Nature.