The orbit of the newly discovered exoplanet resembles that of a ‘cucumber’

The gas giants in our solar system – Jupiter and Saturn, along with their ice giants Uranus and Neptune – orbit far from the sun. However, that’s not the case for some of the giant planets we’ve discovered outside the solar system. Many of them are extremely close to their stars, closer than Mercury is to our sun. These close-in giants are often mentioned ‘hot Jupiters’, and a new one paper published on July 17 in the magazine Nature promises to shed some light on the process of their formation.

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The study describes a newly discovered exoplanet called TIC 241249530. The research team discovered its presence in data from the Transiting Exoplanet Survey Satellite (TESS) and studied its properties through various telescopes and other instruments. They concluded that the planet is about five times as massive as Jupiter, and that it orbits a star that is “slightly hotter, larger and more massive than the Sun.” However, it’s the way TIC 241249530 orbits that star that makes it especially notable. The planet’s orbit is extremely eccentric or highly elliptical. In fact, its orbit is the most eccentric ever observed in an exoplanet; according to the research teamThe trajectory of 241249530 is “closer to a cucumber than a circle.” The planet’s orbit is made even stranger by the fact that it is “reverse”: TIC 241249530 moves in the opposite direction of its star’s rotation.

The orbit of TIC 241249530 is not only remarkable for its extreme nature, but also provides evidence for a theory of how hot Jupiters form, and how they end up so close to their parent stars. That theory suggests that the planets merge at relatively large distances from their stars, but over time migrate inward and enter eccentric orbits that bring them extremely close to their parent stars. As each pass reaches its periastron – the point at which the planet comes closest to the star – tidal forces leak energy from the planet’s orbit, eventually causing that orbit to stabilize in a very tight circle close to the star.

It appears that this is exactly what is happening with TIC 241249530, giving astronomers a chance to watch the process as it unfolds. “This exoplanet serves as a kind of snapshot of the migration process. Planets like this are hard to find and we hope it can help us unravel the hot story of Jupiter’s formation,” said Arvind Gupta, co-author of the study and postdoctoral researcher at NOIRLab, in a rack.

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Although such planets are indeed rarely observed, we have seen at least one exoplanet similar to TIC 241249530: HD 80606b, first described in a Paper from 2001. HD 80606b is another immense planet, just over four times the mass of Jupiter, and was the record holder for orbital eccentricity in an exoplanet until the discovery of TIC 241249530. Notably, both this planet and TIC 241249530 appear to follow the predicted type trajectory . by the inward migration theory. As such, this new discovery presents further evidence in support of that theory.

However, TIC 241249530 also promises to provide a wealth of new information about hot Jupiters. Scientists can obtain a lot of data about exoplanets by observing them as they pass by their parent stars, that is, from our vantage point in front of the star. TIC 241249530 reaches its periastron – the point at which it is closest to its parent star – just six hours before its transit. As the paper notes, this “provides a unique opportunity to observe how [the planet’s] the atmosphere is responding to… rapid, extreme warming” – an opportunity that will hopefully allow us to make direct observations of the exotic processes that keep these massive planets orbiting extremely close to their stars.