A fast-orbiting exoplanet appears to be the youngest of those found in the past few years. It’s nearly an infant at the age of somewhere between 5 million and 10 million years old guess researchers as that is the same age of the young star it orbits every five days.
Neptune-size exoplanet is all sorts of close to its star
Clearly, Mercury is the closest planet to our sun and it makes tracks around the sun quite quickly compared to Earth’s 365.25 day orbit. K2-33b, however, puts this to shame with an orbit of just five days. Think professional Kenyan marathon and a high-school marathon team where all the members of the team still think it’s cool to smoke. The planet, roughly the size of Jupiter, is among one of the nearly 1,300 exoplanets found and verified by the Kepler Space Telescope in addition to hundreds of solid candidates even if gas giants.
Not only is K2-33b orbiting its star at only 1/10th the distance that Mercury orbits our sun, but researchers have determined that it’s a babe-in-the-woods in astronomical terms.
“Our Earth is roughly 4.5 billion years old,” Trevor David, a graduate student researcher at the California Institute of Technology and lead author of the new study, said in a statement accompanying publication of he and his teams finding. “By comparison, the planet K2-33b is very young. You might think of it as an infant.”
The planet is one of two infants that were identified and written about were published in Monday’s issue of Nature.
The discovery of K2-33b was, not surprisingly, part of the re-purposed K2 mission of the Kepler Space Telescope and was made thanks to the transit method. That’s to say the planet was verified to to dimming and brightening of the star that Kepler was observing which effectively prove that the planet was crossing between the star and Kepler (in this case every five days). Researchers are hoping to use this exoplanet to glean a better understanding of planets in their formative years and infancy.
Data from the Keck Observatory in Hawaii and NASA’s Spitzer Space Telescope confirmed the find by Kepler.
“Initially, this material may obscure any forming planets, but after a few million years, the dust starts to dissipate,” Ann Marie Cody, a postdoctoral researcher at NASA’s Ames Research Center in California, said in the statement made at the same time as publication. “It is during this time window that we can begin to detect the signatures of youthful planets in K2.”
Puzzling proximity to its star
Most planets of 33b’s mass are believe to form considerably further from the star they orbit and over hundreds of millions migrate closer to their stars before staying in an almost fixed orbit. But given the planets age this couldn’t be the case and researchers are a bit puzzled.
“After the first discoveries of massive exoplanets on close orbits about 20 years ago, it was immediately suggested that they could absolutely not have formed there,” David said. “But in the past several years, some momentum has grown for in situ formation theories [that the planet could form right where it is], so the idea is not as wild as it once seemed.”
Alternatively, the planet could have formed farther away from its star and quickly migrated through the process known as disk migration where the planet essentially “catches a wave” on a disk of debris and gas which also orbits the same star.
“After the first discoveries of massive exoplanets on close orbits about 20 years ago, it was immediately suggested that they could absolutely not have formed there,” David said. “But in the past several years, some momentum has grown for in situ formation theories [that the planet could form right where it is], so the idea is not as wild as it once seemed.”
“The question we are answering is, did those planets take a long time to get into those hot orbits, or could they have been there from a very early stage? We are saying, at least in this one case, that they can indeed be there at a very early stage,” he continued.
Now that the discovery of its age has been made, researchers will be spending more and more time trying to understand the early years of planets as well as trying to determine if the planet raced towards its star in a disk migration of if it truly formed where it presently orbits the star. The latter would cause quite the rethink in what astronomers thought they new about planet formation.
