Primary star HD 131399 A is a spectroscopic binary, using Aa1 and Aa2 as the
component designations as these are not yet assigned, and Ab is already used
for the planet candidate. Lagrange et al. (2017)
https://www.aanda.org/articles/aa/pdf/forth/aa30978-17.pdf
Planet is likely a background star. Nielsen et al. (2017) http://adsabs.harvard.edu/abs/2017AJ....154..218N
Primary star HD 131399 A is a spectroscopic binary, using Aa1 and Aa2 as the component designations as these are not yet assigned, and Ab is already used for the planet candidate. Lagrange et al. (2017) https://www.aanda.org/articles/aa/pdf/forth/aa30978-17.pdf
Position angle and separation for the HD 131399 BC binary from WDS http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-ref=VIZ5a2be9538522&-out.add=.&-source=B/wds/wds&recno=80499
K-magnitudes for BC, missing orbital elements for A-BC and BC from Wagner et al. (2016) http://adsabs.harvard.edu/abs/2016Sci...353..673W
Parallax and additional identifiers from SIMBAD