2024-05-27 Update to Gaia DR3 known issue "NSS: False-positive astrometric binary solutions"

A few new cases of false-positive astrometric binary solutions were identified. These cases have been added now to the Gaia DR3 known issue "NSS: False-positive astrometric binary solutions".

The text now reads:

During validation of the astrometric timeseries (epoch astrometry) for Gaia DR4, an error was discovered that had already had an impact on the Gaia DR3 non-single star results published in the gaiadr3.nss_two_body_orbit table. The investigation showed that four specific targets suffered of this software bug and that the astrometric-orbit solutions of Gaia DR3 4698424845771339520 (WD 0141-675), Gaia DR3 5765846127180770432 (HIP 64690), Gaia DR3 522135261462534528 (54 Cas), and Gaia DR3 1712614124767394816  (HIP 66074) are false-positives as far as Gaia non-single star processing is concerned. The former two cases had already been reported here in May 2023. Independently, the HIP 64690 orbit solution was identified as spurious by Spaeth et al. 2023 (DOI 10.3847/2515-5172/acb3c5).
 
The Gaia DR3 4698424845771339520, Gaia DR3 522135261462534528, and Gaia DR3 1712614124767394816 entries in gaiadr3.binary_masses are no longer valid as they were based on the orbit solutions. For all four sources,  the astrometric and other parameters in the gaiadr3.gaia_source table are not affected and remain valid.
 
An internal investigation of astrometric orbit solutions of sources with inferred substellar-companion candidates did not reveal additional false-positives. The new status of the HIP 66074 DR3 orbital solution as false positive does not put into question the radial-velocity discovery of an exoplanet around this source by Sozzetti et al. 2023 (DOI 10.1051/0004-6361/202347329).