Inside MOND: testing gravity with stellar accelerations

Abstract

Abstract We quantify the differences between stellar accelerations in disk galaxies formed in a MONDian universe relative to galaxies with the identical baryonic matter distributions and a fitted cold dark matter halo. In a Milky Way-like galaxy the maximal transverse acceleration is  𝒪(10-9) arcseconds per year per decade, well beyond even the most optimistic extrapolations of current capabilities. Conversely, the maximum difference in the line-of-sight acceleration is 𝒪(1) centimetre per second per decade at solar distances from the galactic centre. This level of precision is within reach of plausible future instruments.