The discovery of the planet took only 3.2 days to orbit the host star

Astronomers have found a "hot Jupiter"-type exoplanet orbiting a star 725 light-years away.

The exoplanet known as TOI-1789b is located very close to the aging star TOI-1789, just 0.05 astronomical units (AU), or one-tenth of the distance from the Sun to Mercury, according to the Research Foundation Indian Space.

Exoplanet simulation TOI-1789b. (Photo: Sci-News)

Scientists from the Physics Research Laboratory (PRL) led by Professor Abhijit Chakraborty spent three months monitoring TOI-1789b using the PARAS spectrometer at the Abu Observatory in Rajasthan state, India and found that The celestial body takes only 3.2 days to complete one orbit. Meanwhile, Mercury takes 88 days to orbit the Sun.

TOI-1789b is a Jupiter-like gas giant, also known as "hot Jupiter". Due to its proximity to its host star, it has a surface heated to 1,727°C and is expanding.

That is why the object has a radius of 1.4 times that of Jupiter even though it is only 70% of the mass. This makes it one of the lowest-density planets known, around 0.31 g/m3. For comparison, Jupiter has a density of 1.33 g/cm³.

The star TOI-1789, which is 1.5 times more massive than the Sun, is thought to be entering the final stages of evolution. This discovery is therefore of very special significance.

"Detecting a system like TOI-1789 will help us better understand the inflating mechanisms of hot Jupiter, as well as provide the opportunity to study the evolution of the stars and planets around. ", Chakraborty shared.

Details of the study are published in the journal Monthly Notices of the Royal Astronomical Society.