SIMBAD references

Background stars within ∼1″ of a nearby massive object will have their centroids shift by about 1 mas due to microlensing. This provides mass measurements of stellar mass objects in the solar neighborhood. Habitable Worlds Observatory (HWO) targets toward the Galactic Bulge will have a sufficient density of background stars that HWO will be able to measure their masses independently of stellar evolutionary models, which will allow more accurate habitable histories of their exoplanets to be evaluated. This opportunity is maximized for designs of HWO with very high contrasts (Δmag ≳25) and the capability for precise relative astrometry with respect to the target star. HWO can apply this technique to any nearby stellar mass object in the direction of the Galactic Bulge, enhancing its science case and that of precursor missions like Roman.