An international team of scientists has observed for the first time an oval planet product of deformation caused by the gravitational force of its host star. This effect, known as a ‘rugby ball’, had so far only been theorized by astronomers.
The results of the research were published this January 11 in the journal Astronomy & Astrophysics.
The article details that the exoplanet (planet from another solar system) WASP-103b it has been warped by the powerful tidal forces between it and its host star, WASP-103, hotter and larger than our Sun.
“This exoplanet takes less than a day to go around its star and its shape is more similar to that of a rugby ball than to that of a sphere”, says Jorge Lillo-Box, researcher at the Center for Astrobiology (CAB) and co-author of the study.
The phenomenon is not strange. On Earth, for example, the tides of the oceans are produced, a result of the influence of the Moon that ‘pulls’ slightly on our planet while it orbits us
The Sun also has a small but significant effect on the tides, but it is too far from Earth to cause large deformations.
In this case, the star around which the exoplanet revolves, called WASP103, in the constellation Hercules, has a similar temperature and is about 1.7 times larger than our Sun.
The exoplanet WASP-103b is a gas giant planet with almost twice the size of Jupiter and 1.5 times its mass and its extreme closeness to its host star could cause gigantic tides, something that until now has not been confirmed.
Using new data from the European Space Agency (ESA) Cheops space telescope, combined with data obtained by NASA / ESA Hubble and NASA Spitzer, the astronomical community has been able to detect how tidal forces deform the exoplanet WASP. -103b, giving it an oval appearance.
These data have been complemented with high spatial resolution images from the AstraLux instrument at the Calar Alto Observatory (Almería), thanks to which the origin of the signal has been confirmed.
Cheops measures the transits of exoplanets; that is, the changes in light that occur when a planet passes in front of its star, but this time, its high precision has allowed it to detect the tiny signal that indicates that WASP-103b is undergoing a deformation caused by tidal forces. .
The Cheops data have also made it possible to derive a parameter called the Love number, which measures how mass is distributed within a planet, which can give information about its internal structure and materials, and determine in what proportion it can be rocky, gaseous. or liquid.
“Understanding this internal structure is essential to understand the processes of formation and evolution of planetary systems,” says Jorge Lillo-Box.
The Love number of the exoplanet WASP-103b is similar to that of Jupiter, suggesting that the internal structure could be similar, despite the fact that WASP-103b has twice the radius.
This is because it is ‘inflated’, probably by the heat emanating from its host star and by other mechanisms that in the future can be studied with the James Webb telescope, the largest space observatory in history that will help to find out much more. on the internal structure and nucleus of exoplanets and, therefore, on their formation.
The study also points out that the orbital period of WASP-103b could be increasing and that the planet is slowly moving away from the star, which would indicate that, along with tidal forces, there is another factor that influences the planet, but it will be more observations are needed to find out why this is happening.
With information from EFE.