An ancient planet, a warm version of Jupiter, has been discovered orbiting the aging G-type dwarf star TOI-5542 in the constellation Pavo.
According to Sci-News, a study conducted by a team of scientists from Switzerland, the UK, the US, the Netherlands, South Africa, and Chile has uncovered one of the oldest planets in the universe within the vast data set of the “exoplanet hunter” TESS (NASA’s space telescope).
The findings have been confirmed by several powerful ground-based telescopes. The ancient planet is named TOI-5542b, after its parent star, located 1,154 light-years away in the constellation Pavo.
Graphic illustration of a warm Jupiter orbiting a G-type dwarf star – (Image: SCI-NEWS).
Astronomer Nolan Grieves from the University of Geneva, the lead author of the study, stated that it is a giant planet similar in size to Jupiter in our Solar System but orbits very close to its parent star, thus classified as a “hot Jupiter.”
“Even with a low occurrence rate of less than 1%, hot Jupiters remain one of the most common groups among known exoplanets, due to the observational bias of current detection methods favoring large, close, and massive planets,” Dr. Grieves explained.
He further analyzed: “Hot Jupiters are affected by intense stellar radiation, which can accumulate energy within, causing them to have a larger radius than expected based on internal structure models. They are also influenced by strong tidal forces, which can lead to tidal locking, reducing orbital eccentricity and the planet’s rotation period, as well as creating a stark contrast between day and night.”
Tidal locking is the phenomenon where a celestial body is strongly affected by the gravitational pull from a larger body it orbits, resulting in it always facing its parent body with one side, similar to how the Moon always shows the same face to Earth.
TOI-5542b can be more specifically classified as a “warm Jupiter”, meaning it is not among the hottest. It orbits its parent star every 75.12 days and has an average temperature of about 168 degrees Celsius.
With a moderately warm temperature and an orbital period of 10-200 days, such exoplanets are close enough to their parent stars to limit planetary evolution models, yet far enough to minimize atmospheric changes caused by the parent star, unlike some extremely close hot Jupiters.
Thus, TOI-5542b may retain many ancient characteristics from its formation, becoming a treasure for researchers who seek to understand the history of planet formation to unravel the mysteries surrounding the origins of Earth and our own planet.
The study has been approved and will be published in the upcoming issue of Astronomy & Astrophysics.
