According to a new study, scientists think that an exoplanet candidate may be shaped like an American football. The planet, named KOI 1843.03, orbits its red dwarf star at such a close proximity that the gravitational force is what’s causing its odd football-like shape. The discovery of the exoplanet was made public in 2013.
The red dwarf star KOI 1843 is located approximately 395 light-years away from Earth and is a little less than half the mass of our sun. The exoplanet KOI 1843.03 measures around 60% of Earth’s diameter and has about 44% of its mass. It’s also believed that the planet is more than likely made up of 66% iron (compared to Earth being made up of around 32% iron) because if it contained less iron it would be ripped apart being so close to its star. "KOI 1843.03 is one of the most iron-enhanced exoplanets discovered to date," stated Leslie Rogers who is an astrophysicist at the University of Chicago as well as the senior author of the new study (which can be read in full here).
And it has an extremely fast orbit – in fact, it makes its way around its star much closer than any other planet previously studied. Rogers went into further detail by explaining to Space.com, “Whizzing around its star in only 4.245 hours, a 'year' for this planet is just over one-sixth of a day on Earth.”
By conducting 3D simulations of the planet’s interior structure in order to find out what type of effects such a close orbit would have on KOI 1843.03, researchers discovered that it may very well be shaped like a football. “KOI 1843.03 is the most aspherical exoplanet discovered to date,” Rogers explained, adding, “Our models show that KOI 1843.03 is significantly elongated along the direction toward its star, having an aspect ratio of up to about 1.8.” For comparison, a wide-screen television has an aspect ratio of 1.7 while a chicken egg has a 1.3 aspect ratio.
Another fact that the researchers mentioned was that they studied nine exoplanets with orbits that last less than an Earth day and they found that four of them are rich in iron. They also mentioned that the planets could possibly be more spherical-shaped than those with the same orbit that contain less iron. Ellen Price, who is an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Massachusetts as well as the lead author of the study, explained to Space.com, “We expect that more iron-rich compositions will lead to less distorted planets,” adding, “There is a trade-off between how extreme the shape of the planet is and how extreme its composition is.”
More research needs to be done on tidally distorted exoplanets, such as how they appear when they travel in front of their stars and if scientists will be able to determine if a planet is distorted based solely on how its shadow appears.