Filippo Mannucci and INAF Florence used Gaia satellite data from the European Space Agency to identify the gravitational lens.
Gaia was originally designed to observe stars in the Milky Way.
Gaia’s resolution and wide field of view make it useful for finding small and rare gravitational lenses.
The study uses rotation-curve measurements from the European Space Agency's GAIA DR3 release for the Milky Way's outer halo.
The research resolved a discrepancy in the ESA Gaia DR3 catalog where the initial Gaia orbital solution for the object indicated a much shorter period and lower eccentricity.
Gaia-6 B is a brown dwarf with a mass of about 20 times that of Jupiter.
Gaia-6 B orbits HD 128717 with an orbital period of approximately 9.37 years.
Intensive high-cadence monitoring with the HARPS-N spectrograph on the INAF Telescopio Nazionale Galileo (TNG) at La Palma enabled precise measurement of Gaia-6 B’s non-circular orbital shape.
A degeneracy in the Gaia DR3 astrometric solution caused the orbital signal of Gaia-6 B to be misinterpreted because the period exceeded the DR3 observation span.
An INAF-led research team confirmed and precisely characterized a new substellar companion orbiting the star HD 128717 named Gaia-6 B.
Gaia-6 B moves on an extremely eccentric orbit, among the most eccentric measured for an object of its mass.
Gaia DR3 observations spanned about 34 months, a duration much shorter than Gaia-6 B’s true orbital period.
Matteo Pinamonti is an INAF researcher and the first author of the Gaia-6 B study.
Gaia-6 B resides in the transition regime between giant gas planets and brown dwarfs.
Future Gaia data releases such as DR4 will provide longer temporal coverage that can confirm and refine the orbital solution for Gaia-6 B.
The same precision propulsion system used on ESA’s Gaia and Euclid missions will be used on each LISA spacecraft to keep laser interferometer beams pointed at remote spacecraft approximately 2.5 million kilometers away.
The authors expect that future Gaia data releases together with ongoing and planned spectroscopic surveys will expand the sample of known runaway massive stars and improve the accuracy of their orbital histories.
The same precision propulsion system approach used on Gaia and Euclid will be applied on LISA to keep the interferometer beams accurately pointed at the remote spacecraft 2.5 million kilometers away.
Major data releases from the Gaia and Euclid missions are planned for 2026.
El proyecto 4MOST, impulsado por la European Southern Observatory, busca complementar las misiones espaciales como Gaia, Euclid y eROSITA.