How can two planets so similar in some respects have such different densities? According to a new study, a catastrophic collision may be to blame.
Imagine a place where the weather forecast is always the same: scorching temperatures, relentlessly sunny, and with absolutely zero chance of rain. This hellish scenario exists on the permanent daysides of a type of planet found outside our solar system dubbed an "ultrahot Jupiter." These worlds orbit extremely close to their stars, with one side of the planet permanently facing the star.
The study of extra-solar planets has revealed discoveries that have confounded expectations and boggled the mind! Whether it’s Super-Earths that become diamond planets, multiple rocky planets orbiting closely together, or “Hot Jupiters” with traces of gaseous metal in their atmospheres, there’s been no shortage of planets out there for which there is no comparison here in the Solar System.
A newly discovered Jupiter-like world is so hot, it’s being vaporized by its own star.With a dayside temperature of more than 7,800 degrees Fahrenheit (4,600 Kelvin), KELT-9b is a planet that is hotter than most stars. But its blue A-type star, called KELT-9, is even hotter -- in fact, it is probably unraveling the planet through evaporation.
The last decade has seen a bonanza of exoplanet discoveries. Nearly 2,000 exoplanets -- planets outside our solar system -- have been confirmed so far, and more than 5,000 candidate exoplanets have been identified. Many of these exotic worlds belong to a class known as "hot Jupiters." These are gas giants like Jupiter but much hotter, with orbits that take them feverishly close to their stars.