Hot Jupiters are among the most extreme planets in the galaxy, characterized by their immense size and scorching temperatures. These massive worlds orbit their stars in just a few days, a stark contrast to Jupiter’s leisurely 4,000-day orbit around the sun.
Scientists believe that hot Jupiters likely began as “cold Jupiters” in distant, colder regions of space. However, the transformation process that turns them into the hot, star-hugging giants we observe today remains a mystery.
Recently, astronomers from MIT, Penn State University, and other institutions have discovered a hot Jupiter “progenitor,” a young planet currently evolving into a hot Jupiter. This discovery provides valuable insights into the evolution of these planets.
The newly identified planet, named TIC 241249530 b, is located approximately 1,100 light-years from Earth. It has an unusually “eccentric” orbit, bringing it extremely close to its star before swinging far out in a narrow, elliptical path. If this planet were in our solar system, it would approach the sun ten times closer than Mercury, then travel just beyond Earth before looping back. This orbit has the highest eccentricity ever detected for a planet.
Additionally, TIC 241249530 b’s orbit is “retrograde,” meaning it moves in the opposite direction of its star’s rotation, unlike the planets in our solar system that orbit in the same direction as the sun spins.
Simulations of orbital dynamics suggest that the planet’s eccentric and retrograde orbit indicates it is undergoing “high-eccentricity migration.” This process involves the planet’s orbit gradually shrinking and becoming more circular as it interacts with another star or planet on a wider orbit, eventually transforming it into a hot Jupiter.
Source https://news.mit.edu/2024/astronomers-spot-highly-eccentric-planet-becoming-hot-jupiter-0717
