A group of astronomers from the Physical Research Laboratory (PRL) in Ahmedabad, India, discovered a new exoplanet. Uniquely, on this planet, a year only lasts a few days.
The team led by Prof. Abhijit Chakraborty of PRL, spotted a planet orbiting a star that is about 1.5 times the mass of our Sun and lies 725 light-years away.
"This discovery was made using the PRL Advanced Radial-velocity Abu-sky Search (PARAS) fiber-optic spectrograph, the first of its kind in India, on the 1.2-meter PRL Telescope at Mt. Abu Observatory," wrote India's national space agency, ISRO.
"These measurements were made between December 2020 and March 2021. Further measurements were also obtained from the TCES spectrograph from Germany in April 2021, as well as independent photometric observations from the 43 centimeter PRL telescope at Mt. Abu Observatory," they added.
The planet, called TOI 1789b or HD 82139b, is about 1.4 times the size of Jupiter, with about 70% of its mass. It also orbits its parent star in just 3.2 days, which means it is very close to the star, at a distance of only 0.05 times the distance between Earth and the Sun. These conditions make it a type of planet called hot Jupiter.
Because the planet is so close to its star, it experiences extremely high temperatures of up to 1,727 degrees Celsius, hot enough to melt iron. The planet is also expanding, so it is very low density, easily swollen, and larger than Jupiter despite its smaller mass.
Similar hot Jupiters have also been discovered using other instruments such as the exoplanet NGTS-10b. The planet was discovered as part of the Next-Generation Transit Survey (NGTS). In addition, KELT-9b was found using the Kilodegree Extremely Little Telescope.
Studying Jupiter's hot twin could help astronomers understand how planetary systems formed and evolved. "The detection of such a system improves our understanding of the various mechanisms responsible for inflation in hot Jupiters and the formation and evolution of planetary systems around evolving and aging stars," ISRO said.
