A high-precision spectrograph at the U.S. National Science Foundation’s Kitt Peak National Observatory has confirmed the existence of a massive exoplanet, Gaia-4b, orbiting a low-mass star. This is the first planet detected by the European Space Agency’s Gaia spacecraft using the astrometric technique.
The spectrograph, NEID, measures the minute wobble of nearby stars caused by the gravitational force between a planet and its host star. In collaboration with the Habitable-zone Planet Finder (HPF) on the Hobby Eberly Telescope in Texas, and the FIES Spectrograph on the Nordic Optical Telescope at La Palma, the team conducted follow-up observations of 28 star systems with planet candidates identified by Gaia.
Twenty-one of these candidate systems were found to be false positives, actually binary star systems. One system was confirmed to host a brown dwarf, while another hosted a giant planet. However, one system was confirmed to host Gaia-4b, a massive exoplanet with an orbital period of 570 days and a mass of 12 Jupiter masses.
Gaia-4b orbits a star 64% the mass of the sun and is one of the most massive planets known to orbit a low-mass star. The detection confirms that Gaia’s astrometric technique can be used to discover planetary companions with high precision.
Source: https://phys.org/news/2025-02-high-precision-spectrograph-massive-exoplanet.html