Least-squares periodogram. The upper panel shows the CLS periodogram obtained by fixing the eccentricity e = 0. There is a prominent peak with a period of 999 days and a FAP of 0.004%. There is an additional peak with a period of 87 days and a FAP close to 0.1%. The lower panel shows the periodogram that was obtained when fixing the eccentricity e = 0.368, which was obtained with the absolute astrometry fit of DoAr21c (see Table 3). The main peak becomes more prominent when including the eccentricity of the orbit. This indicates that this is a better fit to the data. The second peak also becomes marginally more prominent, suggesting that the orbit of this companion may also be eccentric.