The sphere is the universe's shape of choice, but sometimes unusual circumstances can cause deviations from the tried and true orb in space.
The European Space Agency (ESA) discovered an exoplanet that orbits so close to its sun that it has deformed into an oval rather than a sphere, a press statement reveals. In other words, the tidal force of the planet's sun is so strong, that it moves the solid ground.
Planet-deforming tidal strength
It is the first time that astronomers have detected the deformation of an exoplanet, proving theories on the gravitational impact of large suns on close-orbiting planets. The planet is called WASP-103b and it orbits its host star WASP-103 in the Hercules constellation. WASP-103 is roughly 200 degrees hotter than our Sun and it is 1.7 times larger.
Our Sun has an impact on our tides, but it's far enough from Earth that this gravitational tidal force hasn't deformed our planet. WASP-103b, on the other hand, orbits its sun in less than a day and it is 1.5 times the mass and almost twice the size of Jupiter. Such close proximity means that it has been warped into the size of a rugby ball — or American football for those on the other side of the pond from ESA — according to the astronomers.
The team of researchers collected the data on WASP-103b from the ESA's Cheops space telescope and combined it with Hubble and NASA's Spitzer Space Telescope data. They presented their findings in the journal Astronomy & Astrophysics.
"The resistance of a material to being deformed depends on its composition," explains Susana Barros of the University of Porto, Portugal, lead author of the paper. "For example, here on Earth we have tides due to the Moon and the Sun but we can only see tides in the oceans. The rocky part doesn't move that much. By measuring how much the planet is deformed we can tell how much of it is rocky, gaseous, or water."
The James Webb Telescope could provide new insight into close-orbiting exoplanets
It's not the first time astronomers have observed planets with incredibly short orbital periods. In December, an international team of astronomers revealed their findings on an exoplanet that is 80 percent composed of iron. The planet, GJ 367b, orbits its red dwarf star in only eight hours. It is so close to its star that its surface is likely composed of seas of molten iron.
Next, the WASP-103b researchers hope to make more observations with Cheops as well as with the recently-launched James Webb Space Telescope to better understand the internal structure of the exoplanet. One mysterious aspect, in particular, has baffled the researchers, and they hope to get new insight with follow-up observations. It is expected that such a large planet on such a close orbit to its star would see its orbital period gradually shorten, meaning it will eventually be engulfed by its star. However, in the case of WASP-103b, initial observations suggest the orbital period is actually increasing and the planet is actually slowly drifting away from its sun. Further observations will hopefully help to solve the mystery and reveal new insight into WASP-103b.