The planets of the solar system are shaped like a globe, but is that the case throughout the universe? The answer seems to be no. A new planet named WASP-103b has been discovered, which is far from a perfect orb that we have in our minds.
The planet, WASP-103b, is located around an F-type star called WASP-103 1500 light-years from Earth. This star is larger and more massive than the Sun, and the planet is also large, about the size of Jupiter, it is about 1.5 times the mass of Jupiter. An international team of astronomers published new findings in Astronomy & Astrophysics on Tuesday detailing the planet’s strange shape for the first time.
Cheops reveals the new planet
Cheops is a satellite of ESA (European Spacce Agency) whose name comes from CHaracterising ExOPlanet Satellite ExOPlanet. It is the first mission dedicated to studying bright nearby stars already known to host exoplanets, in order to make high-precision observations of the planet’s size as it passes in front of its host star. It will focus on planets in the size range from Earth to Neptune, and its data will allow deriving the bulk density of the planets, a first-step characterization toward understanding these alien worlds. More data on the deformed planet can be found in Fig. 1, source ESA.
Cause of its deformed size of the planet
It appears that due to its proximity to its local star (less than 20,000 miles) and the stresses that occur cause WASP-103b to take on an unlikely shape, which astronomers have compared to a rugby ball. It also looks a bit like an egg or a potato.
If we consider the solar system we are in, planets exist millions of kilometers from the host star, and take at least a few months, a year (like Earth) or many years to complete an orbit around the Sun. But a group of exoplanets known as Hot Jupiters orbit their home stars in a matter of days, sometimes just hours. These planets are known as ultra-short period planets.
When it was discovered
Astronomers initially discovered WASP-103b in 2014 and noticed at the time that the planet must experience strong tidal stresses due to its proximity to its home star: it orbits WASP-103 (the star) in just 22 hours, that is, its year is 22 hours. This is not the shortest orbital period known (some exoplanets with periods of less than 10 hours have been found), but it is short enough to make WASP-103b an extreme world.
When it was discovered, scientists suspected it might have an unusual model-based shape, though it wasn’t confirmed, until now. Future observations with the James Webb Space Telescope will allow in the future to have a sharper image of this planet in such a peculiar way.
Why the discovery of new planets is important?
To date, astronomers have discovered 4,884 planets and have around 8,400 candidates they are working to confirm. All of these planets come in different shapes, sizes, and configurations. Such a large amount of data helps astronomers refine how planets form and how systems like ours arise, as well as challenging our assumptions.
This includes understanding the tidal stresses that stars exert on their planets. Most ultra-short period planets are doomed as their star extracts material or shatters them. But in a strange twist, astronomers believe that WASP-103b is moving away from WASP-103, rather than approaching, which could spare it this dire fate.