Keplerian orbit fit of HR 8799 e. The black point is the GRAVITY measurement, and the gray points are from previous astrometry (Konopacky et al. 2016; Wang et al. 2018a). The yellow lines are 250 random draws from the posterior. The orbit determination is currently limited by the mas-level astrometry of the previous epochs (top inset). Image magnified by ∼200x to display the uncertainties in the GRAVITY astrometry. The plotted error bars are rotated to be aligned with the principal axes of the error ellipse. Bottom inset: image magnified by ∼2x to display the uncertainties in the previous measurements.