Discovery of a nascent planet in close orbit around a young star

A study conducted by a team of scientists from the Institut de Planétologie et d’Astrophysique de Grenoble (IPAG - CNRS / UGA) as part of the ERC SPIDI project, has revealed the presence of a massive nascent planet in close orbit around a young star in the Taurus constellation, named CI Tau.

Just 2 million years old - the equivalent of barely a week on a human scale - it is a planet with a mass 3.6 times that of Jupiter, and a period of revolution around the star of 25 days. Such giant planets orbiting their host star in just a few days are known as "hot Jupiters", due to the intense radiation they receive close to their star. This is the youngest planet of this type, still in its formative stages, discovered to date.

This discovery is the result of the simultaneous use of several cutting-edge observational techniques. Firstly, high-resolution spectroscopy from the Canada-France-Hawaii Telescope, located at an altitude of 4,200m at the summit of Maunakea (Hawaii, USA), which enables us to detect the displacement imparted to the star by the planet along its orbital motion. Secondly, multi-wavelength photometry using the Las Cumbres Observatory network of telescopes distributed along the Earth’s surface, and ultra-high-precision space photometry using the Kepler satellite, both of which enable us to detect variations in the brightness of the central star modulated by the planetary orbit.

In particular, this result shows that massive planets can form on very short timescales in the disk of gas and dust surrounding young stars, then rapidly migrate towards the central star on ever-tighter orbits before the disk dissipates in a few million years. The study sheds new light on the complex process of planet formation and evolution in young stellar systems.

Reference

Manick, R., Sousa, A., Bouvier, J., et al. Long period modulation of the classical T Tauri star CI Tau: evidence for an eccentric close-in massive planet at 0.17 au (2024) Astronomy & Astrophysics. DOI : 10.48550/arXiv.2403.03706

This article has been published by CNRS-INSU.