In a recent study published in the journal Monthly Notices of the Royal Astronomical Society, A team of international researchers has examined the exoplanet TOI-4860 b, located about 261 light-years from Earth. Which has an orbital period of about 1.52 days. A low-mass star, that is, a star smaller than our sun.
TOI-4860 b is unique due to its size relative to its parent star, as well as its surface temperatures Less than those found in “hot Jupiters” because they contain large amounts of heavy elements.
These features explain why researchers classify TOI-4680 b as a “hot Jupiter.” It could challenge traditional models of planetary system formation, while providing new insights into these processes. Dr George Dransfield of the University of Birmingham and co-author of the study said: “According to the basic model of planet formation, the lower the mass of a star, the lower the mass of the disk of material around that star.”
Dr George Dransfield of the University of Birmingham and co-author of the study said: “According to the basic model of planet formation, the lower the mass of a star, the lower the mass of the disk of material around that star.”
“Since the planets originate from this disk, it was expected that planets with high masses such as Jupiter would not form.. However, we were interested in this and wanted to check out the candidate planets to see if this was possible. TOI-4860 is our first confirmation that it is the least massive star capable of hosting such a massive planet.”
What are the dimensions of TOI-4860b?
In the study, the researchers used nearly 10,000 observatories and instrumentsincluding TRAPPIST-South/North, SPECULOOS South Observatory and MuSCAT3, to collect optical and spectral data on various transits of TOI-4860 b that passed in front of its parent star.
in the end of the day, The researchers concluded that TOI-4860 b has a diameter of about 0.76 radii of Jupiter, while its parent star is about 0.34 radius of our Sun.. For comparison, the radius of Jupiter is about 70,000 km, while the radius of the Sun is about 0.34 km. It is about 700,000 km across, making Jupiter’s radius about 10% of our sun.
Using these numbers, the radius of TOI-4860 b is about 53,000 km, and the radius of its parent star is 238,000 km, so TOI-4860 b has a radius of about 22% of the radius of its parent star.
How did such a massive exoplanet form around such a small star?
Dr Amory Treaud, Professor of Exoplanetology at the University of Birmingham and lead author of the study, said: ‘The evidence for what might have happened is hidden in the properties of the planets, which appear to be particularly rich in heavy elements.’
“We also detected something similar in the host star. Therefore, it is possible that the abundance of heavy elements stimulated the process of planet formation.The researchers determined that TOI-4860 b contains heavy elements based on its density, which is 1.55 times greater than that of Jupiter, and is mostly composed of lighter elements such as hydrogen and helium.
The researchers found that TOI-4860 b contains heavy elements based on its density, which is 1.55 times that of Jupiter.
Based on these results, and particularly regarding TOI-4860 b’s large radius relative to its parent star, the researchers refer to TOI-4860 b as a “hot Jupiter”, since Its surface temperature is about 350 degrees Celsius, which is much lower than the temperature of the “hot Jupiters”, some of which can reach temperatures of 2750 degrees Celsius on the day side.s.
Previous studies have determined that hot Jupiters have orbital periods of more than 10 days, and that their systems also harbor additional planets. So, TOI-4860 provides astronomers with a unique opportunity to examine these unique exoplanets and gain insights into their formation and evolution..
In 2019, astronomers confirmed the existence of TOI-677 b, a Jupiter-sized exoplanet located about 463 light-years from Earth, with an approximate surface temperature of 979 degrees Celsius.
For the next steps, the researchers plan to use the Very Large Telescope in Chile, hoping to identify other hot Jupiters, or even exoplanets with similar characteristics.
