NASA's upcoming Nancy Grace Roman Space Telescope may detect dozens of isolated neutron stars in the Milky Way through gravitational microlensing. A new study shows the observatory could measure the masses of these otherwise invisible objects. Researchers expect the mission to provide the first large sample of such stars detected solely by their gravitational effects.
Astronomers estimate the Milky Way contains tens to hundreds of millions of neutron stars, yet only a few thousand have been identified, mostly as pulsars. Most remain hidden because they emit little or no detectable light. The Roman telescope will repeatedly observe millions of stars in the galactic bulge, allowing it to spot the subtle brightening and positional shifts caused when a neutron star passes in front of a distant background star.