European Space Agency discovers Jupiter-like exoplanet shaped like a rugby-ball

In a fascinating new discovery, the European Space Agency (ESA) under its Characterising Exoplanet Satellite (Cheops) exoplanet mission has discovered a planet deformed like a rugby ball. Surprisingly, this conventionally shaped planet named WASP-103b orbits its star in just one day, a characteristic which is being attributed for its stretched shape instead of a spherical one. The ESA says that this is the first time scientists have detected the deformation of an exoplanet. 

What caused the planet’s deformation?

Scientists from the ESA explained that the exoplanet’s proximity to its host star dubbed WASP-103 is the reason for its rugby-ball shape. The planet deformed from the strong tidal forces that were generated owing to the gravitational tug of war between the planet and the star, which is about 200 degrees hotter and 1.7 times larger than the Sun.

Scientists have long known that even Earth experiences this gravitational pull from the Moon which causes tides in the planet's oceans. ESA said that even the Sun has a small but significant effect on the ocean tides but this won’t cause deformation of the Earth due to the immense distance between the two. However, this is not the case with WASP-103b, which is twice the size of Jupiter and 1.5 times more massive.

According to ESA, the astronomers used data from ESA’s Cheops space telescope and combined it with the existing data gathered by the Hubble Space Telescope and NASA’s Spitzer Space Telescope. Just like the Transiting Exoplanet Survey Satellite (TESS), Cheops also measures exoplanet transits, which is the dip in light caused when a planet passes in front of its star. Using the high precision and pointing ability of ESA’s satellite, the scientists were able to detect the minute signal of the tidal deformation in the deformed planet.

Astronomer Jacques Laskar, the co-author of the research said in an ESA statement, "It’s incredible that Cheops was actually able to reveal this tiny deformation. This is the first time such analysis has been made, and we can hope that observing over a longer time interval will strengthen this observation and lead to a better knowledge of the planet’s internal structure”.

In addition to the deformity, Cheops has unveiled another mystery regarding the orbital period of WASP-103b. Scientists say that such tidal interactions between the deformed planet and the star should have caused the former’s orbit to shorten but observations suggest otherwise. With this new revelation, astronomers now believe that a factor other than tidal forces is affecting this planet.

(Image: @ESA/Twitter)