\[fig:pm\], which shows the motion of the 99 Her system. The system proper motion is $\mu_\alpha \cos \delta = -110.32$mas yr$^{-1}$, $\mu_\delta = 110.08$mas yr$^{-1}$ [@2007ASSL..350.....V], and accounts for the motion of the primary assuming the orbit derived in , which is very similar to ours. The small proper motion uncertainty means STIS and @2008AN....329...54S cannot have seen the same object if it is fixed on the sky. There is no clear sign of a third component in the residuals from fitting the orbit of the secondary.

![Motion of the 99 Her system (filled dots) in sky coordinates at three epochs. The epochs including the putative third component are enclosed in boxes. The arrow shows the direction of the system center of mass movement and the distance travelled in 5 years, and the grey lines show the path traced out by each star. Star symbols show the position of the third object observed in the STIS data in 2000 (dashed box) and by @2008AN....329...54S in 2005 (dotted box).[]{data-label="fig:pm"}](pm.eps){width="50.00000%"}

![Keck/NIRC2 adaptive optics image of 99 Her at 3.8$\mu$m, cropped to about 1.5” around the primary. North is up and East is left. The saturated A component is at the center of 