Astronomers have discovered a massive exoplanet and a brown dwarf using data from the European Space Agency’s Gaia mission. The two objects, Gaia-4b and Gaia-5b, are orbiting low-mass stars in our galactic neighbourhood, challenging current theories of planet formation.
Gaia-4b is a “Super-Jupiter” exoplanet with an orbital period of 570 days, while Gaia-5b is a brown dwarf with a mass similar to that of 21 Jupiters. Both objects are orbiting nearby stars, which are extremely rare and thought to be difficult to detect.
The discovery was made possible by Gaia’s ability to sense the gravitational tug or “wobble” caused by the exoplanet or brown dwarf on its parent star. This technique allows astronomers to detect planets in distant orbits around low-mass stars, a scenario previously thought to be extremely rare.
Gaia-4b is about 12 times more massive than Jupiter, while Gaia-5b is a brown dwarf that cannot sustain nuclear fusion to be a star. The discovery provides valuable data for understanding these intriguing objects and challenges current theories of planet formation.
The Gaia spacecraft has been building the largest three-dimensional map of our galaxy since its launch in 2013. With its ongoing mission, scientists expect to discover thousands of new objects in its data, providing insights into how different objects form. The upcoming fourth Gaia data release is expected to be a treasure trove for planet hunters, revealing hundreds or even thousands of planets and brown dwarfs around nearby stars.
This discovery marks an exciting breakthrough in the use of Gaia astrometry for exoplanet detection and complements other established methods used by ESA’s Cheops and the upcoming Plato mission.
Source: https://www.esa.int/Science_Exploration/Space_Science/Gaia/Wobbling_stars_reveal_hidden_companions_in_Gaia_data