Exoplanets come in a wide variety of shapes, sizes, and strange characteristics. There are football-shaped exoplanets, ones where it rains gemstones, planets with the density of cotton candy, and even those with a lava hemisphere. But new research has uncovered an exoplanet, dubbed TIC 241249530 b, that’s unusual in a different way: it boasts one of the most extreme orbits ever discovered.
Most planets, including those in our solar system, don’t have perfectly circular orbits around their stars. Instead, their orbits are slightly elongated. This degree of elongation, known as eccentricity, is measured on a scale of 0 to 1, where 0 signifies a perfectly circular orbit and 1 represents an extremely stretched one. For instance, Pluto has a highly elongated orbit compared to other planets in our solar system, with an orbital eccentricity of 0.25. In contrast, Earth has a much more circular orbit, with an eccentricity of just 0.02.
However, the newly discovered planet has an almost unheard-of orbital eccentricity of 0.94. To illustrate this in terms of our solar system, NOIRLab explains that if this planet orbited our sun, it would swing from a point 10 times closer to the sun than Mercury does, all the way out to Earth’s orbit. This translates to a dramatic temperature swing, going from a warm summer’s day to hot enough to melt titanium.
This extreme temperature fluctuation has captivated scientists, who are eager to study its implications for the planet’s atmosphere. “We’re especially interested in what we can learn about the dynamics of this planet’s atmosphere after it makes one of its scorchingly close passages to its star,” said Jason Wright, a researcher from Penn State. “Telescopes like NASA’s James Webb Space Telescope have the sensitivity to probe the changes in the atmosphere of the newly discovered exoplanet as it undergoes rapid heating, so there is still much more for the team to learn about the exoplanet.”
Researchers are also intrigued by how the planet’s orbit evolves over time. They predict that the tidal forces exerted by its close proximity to the host star will gradually cause the planet’s orbit to become more circular. This planet is classified as a hot Jupiter, a type of planet similar in size to Jupiter but orbiting much closer to its star. These planets are commonly found outside our solar system, but astronomers are still uncertain about how they end up so close to their stars. The prevailing theory is that they form farther out and migrate closer over time.
Studying this newly discovered planet could provide valuable insights into this process. “While we can’t exactly press rewind and watch the process of planetary migration in real time, this exoplanet serves as a sort of snapshot of the migration process,” said lead researcher Arvind Gupta of NOIRLab. “Planets like this are incredibly rare and hard to find, and we hope it can help us unravel the hot Jupiter formation story.”
