An international team of scientists has utilized NASA's TESS (Transiting Exoplanet Survey Satellite) to discover a new exoplanet, TOI-3261 b, followed by observations from ground-based telescopes across Australia, Chile, and South Africa. This planet is categorized within the 'hot Neptune desert', a rare class of exoplanets.
TOI-3261 b, similar in size and composition to Neptune, orbits its star in just 21 hours, placing it in an exclusive group of ultra-short-period hot Neptunes with precisely measured masses. The discovery of such a planet is significant for testing new models of planet formation, especially given the challenges of retaining a thick atmosphere in such close proximity to a star.
The gravitational and energetic forces from stars can strip away gaseous atmospheres, leading to the hypothesis that TOI-3261 b may have originally been a larger gas giant. The science team estimates the star-planet system is approximately 6.5 billion years old, with the planet likely losing mass through photoevaporation and tidal stripping.
One of the most intriguing aspects of TOI-3261 b is its remaining atmosphere, which could provide insights into its formation history. The planet is about twice as dense as Neptune, suggesting that lighter atmospheric components have been lost over time. Future observations in infrared light, potentially using NASA's James Webb Space Telescope, may reveal the molecular composition of the atmosphere, shedding light on the physical processes governing hot giant planets.
This discovery not only enhances our understanding of TOI-3261 b but also contributes to broader knowledge of atmospheric dynamics in exoplanets within the hot Neptune category.