Planets generally have spherical shape. However, it has been theorized that some might have a Oval shaped caused by the effect of tides. It was just a theory, but now we finally have data on the existence of an oval exoplanet: the WASP-103b.
It has been discovered thanks to data recently obtained by the Cheops Space Telescope, of the European Space Agency (ESA), in combination with older data, from the Hubble, from ESA and NASA, and the Spitzer, from NASA. In addition, high resolution images captured thanks to the instrument have been used. AstraLux, which is located in the Calar Alto Observatory, in Almería.
Its shape is very curious, but it is not the only interesting information that has been obtained from this oval exoplanet. The scientists, whose results have just been published in Astronomy and AstrophysicsThey also have very useful data on its composition, which could even help to understand its origin. And there is also some hint out there that perhaps the star around which it revolves is accompanied by another. There are many mysteries to be solved. But let’s start with what we know so far.
The importance of tidal interactions
Both the star around which the planets revolve and the possible satellites that orbit them generate a gravitational attraction that translates into the forces known as tide.
On Earth, for example, the most relevant manifestation of these is the rise and fall of the sea level, caused by the slight pull exerted on our planet by the Moon. The Sun is also influencing, but it is too far away to cause large deformations.
Now, what if it were much closer? For years it has been theorized that tidal forces could be so great as to warp the planet; so that, instead of the typical spherical shape, it acquired one of rugby ball.
This was a probable suspicion, but it has not been possible to confirm it until Cheops has finally found a oval exoplanet.
An oval exoplanet like a rugby ball
The main function of the Cheops Space Telescope is to locate exoplanets through the transit method.
This method consists of detecting fluctuations in the light of a star that indicate that an object is periodically passing between it and the place from which we observe. On this occasion, said traffic was detected around WASP-103, a star that is part of the Hercules constellation. It has a temperature similar to that of our Sun, but it is 1.7 times larger. For this reason, when they found a planet very close and rotating around it whose transit denoted twice the size of Jupiter and 1.5 times its mass, the authors of this research, in which astronomers from the CSIC Astrobiology Center, they thought that the intense gravitational interaction between them could give rise to tides that deform the exoplanet.
Cheops is a very precise telescope, with a great targeting flexibilityor, in such a way that it allowed to detect the almost imperceptible signals that reveal a deformation that turns it into an oval exoplanet.
And thanks both to this telescope and to the rest of the instruments mentioned, we know even more things. For example, it has been possible to calculate its love number. This is a figure that refers to how mass is distributed within a planet. And this is very important; since, as explained in a statement by one of the study authors, Jorge Lillo-Box, “Understanding the internal structure is essential to understand the processes of formation and evolution of planetary systems.”
The number of Love by WASP-103b it has turned out to be similar to that of Jupiter. That would indicate a similar internal structure. But we must not forget that it has twice the radius. This would indicate that it is inflated, perhaps by the heat coming from its star, but perhaps also by other mechanisms yet to be discovered.
Mysteries to be solved
The authors of this finding hope to continue discovering interesting facts about this oval exoplanet. They will do so thanks to the instruments and telescopes they have already used, but they also hope to have the James Webb Space Telescope, once it is operational.
Among those questions to which you want to give an answer, one of the most enigmatic is your movement. And it is that, given its size and its proximity to its star, the logical thing would be that the tidal interactions made them get closer and closer, until finally it was swallowed by the star. However, it has been seen that, in reality, he is slowly moving away from her.
This leads to think that there may be a second star that is affecting that gravitational pull, avoiding disaster.
But that is not yet known. Much remains to be discovered about this oval exoplanet. For now, its shape is already a find, but this has only just begun.